Series route: This guide belongs to the complete PSLE Learner’s Guide volume directory. The original PSLE Learning Guide supplies the wider English, Mathematics and Science route, while PSLE English provide verified subject-specific continuation.
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This volume solves one precise learner problem: the learner writes a smooth-looking sentence such as “Singapore’s rainfall is higher than London” and accidentally compares rainfall with a city rather than comparing rainfall with rainfall. The goal is durable control, not a remembered slogan. A Primary 6 learner should be able to identify the trigger, explain the mechanism, perform the decision under time pressure and reject an attractive answer that exceeds the evidence.
- Start with the exact mistake and the evidence boundary.
- Build the mechanism before memorising a shortcut.
- Study worked contrasts and name why the near-miss fails.
- Repair misconceptions with one targeted check each.
- Attempt graded independent practice before reading the explanations.
- Return after a delay and prove that the method transfers.
- Use the parent and tutor notes after the learner has attempted the work.
The problem beneath the mistake
A comparison is valid only when both sides name comparable things. “The population of Town A is larger than Town B” places a population on one side and an entire town on the other.
The intended meaning is easy to recover: the writer wants to compare the population of Town A with the population of Town B. Repeating the whole noun phrase is accurate but clumsy.
English solves the repetition with a substitute. Use “that of” for a singular comparison noun: “The population of Town A is larger than that of Town B.”
Use “those of” when the repeated comparison noun is plural: “The results of Class A were better than those of Class B.” Results are compared with results.
Do not insert “that of” mechanically after every comparative. “Town A is larger than Town B” already compares one town with another town and needs no substitute.
The hidden task is to identify the head noun that the comparative actually describes. Words around it may include possessives, prepositional phrases and modifiers that conceal the mismatch.
A possessive can also carry the omitted noun: “Mina’s score was higher than Ravi’s.” Here Ravi’s means Ravi’s score, so the comparison remains balanced.
Faulty comparison is not merely a style problem. It can change the literal claim and weaken a comprehension answer, report or composition even when the reader guesses the intended meaning.
The repair should preserve number, ownership and scope. “That” replaces one thing; “those” replaces several things; the following “of” phrase identifies whose or which things are meant.
The safe routine is underline, name, match and compress: underline the comparative, name the item on the left, rebuild the same item on the right, then compress the repetition only if useful.
Core decision: Compare the same kind of thing on both sides. If repeating a singular noun phrase would be awkward, use “that of”; if the repeated noun is plural, use “those of”. Do not use either form when the two complete subjects are already comparable.
Comparative grammar encodes a relationship between two referents on a shared dimension. A grammatical substitute such as that or those prevents repetition while preserving the category, number and ownership of the missing noun phrase.
Mechanism: why the rule works
1. Find the comparative trigger
Locate words such as higher, lower, larger, smaller, better, worse, more, less, similar to or different from.
The trigger tells you that two sides must be placed on one comparison scale.
Diagnostic check. Which word creates the comparison?
2. Name the left comparison item
Ignore decorative detail and identify the head noun actually being measured or judged.
In “the cost of the red plan”, cost is the comparison item; red plan merely identifies which cost.
Diagnostic check. What exact thing receives the comparative description?
3. Rebuild the full right side
Temporarily repeat the left head noun on the right: “the cost of the blue plan”.
If the full version makes sense, you have exposed the omitted material and can decide whether to compress it.
Diagnostic check. What complete noun phrase would make the comparison literal?
4. Choose that or those by number
Use that for a singular count noun or an uncountable comparison noun; use those for a plural noun.
“The quality … that of” is singular, while “the prices … those of” is plural.
Diagnostic check. Is the omitted head noun one item, a mass idea or several items?
5. Preserve the identifying phrase
The word of normally introduces the owner, place, group or category whose noun is being substituted.
Removing the identifying phrase can leave the substitute without a clear referent.
Diagnostic check. Whose or which version of the repeated noun is intended?
6. Recognise possessive substitution
A possessive form can replace the full right noun phrase: “Aisha’s result exceeded Ben’s.”
The apostrophe form means Ben’s result, not Ben as a person.
Diagnostic check. Can a clear possessive carry the omitted noun naturally?
7. Avoid unnecessary substitution
If the sentence compares one city with another city, one learner with another learner or one method with another method, the nouns already match.
Adding that of can distort a correct comparison.
Diagnostic check. Are the two visible subjects already the same kind of thing?
8. Check meaning after compression
Expand that or those back into the original head noun and reread the sentence.
A correct substitute must preserve number, reference and the intended comparison direction.
Diagnostic check. Does the expanded version say exactly what the compressed sentence claims?
Worked examples: make the decision visible
Pause before each answer. State the controlling evidence in one line, then complete the operation. The explanations deliberately contrast a valid route with a plausible but invalid one, because transfer grows when the learner can say why a tempting route does not apply.
Worked example 1: Population mismatch
Task. Repair: “The population of Pine Town is larger than Cedar Town.”
Reasoning. The left item is a population; the right side names a town. Rebuild “the population of Cedar Town”.
Answer. The population of Pine Town is larger than that of Cedar Town.
Independent check. Expand “that” to “the population” and confirm the two sides match.
Contrast-and-transfer pass. Keep the governing principle from “Population mismatch”, but change one surface detail in the task: Repair: “The population of Pine Town is larger than Cedar Town.” Before recalculating or rewriting, name which evidence remains controlling and which detail has changed. The original conclusion—The population of Pine Town is larger than that of Cedar Town.—may remain valid only if the changed detail does not alter the trigger, relationship or scope. Use the independent check again rather than trusting visual similarity. This second pass trains selection: the learner must decide whether the same method still applies, adapt one step when a condition changes, and refuse the method when its trigger disappears.
Worked example 2: Plural results
Task. Repair: “The results of Group A were more consistent than Group B.”
Reasoning. Results are plural, so the right side must mean the results of Group B.
Answer. The results of Group A were more consistent than those of Group B.
Independent check. Those expands to results and agrees in number.
Contrast-and-transfer pass. Keep the governing principle from “Plural results”, but change one surface detail in the task: Repair: “The results of Group A were more consistent than Group B.” Before recalculating or rewriting, name which evidence remains controlling and which detail has changed. The original conclusion—The results of Group A were more consistent than those of Group B.—may remain valid only if the changed detail does not alter the trigger, relationship or scope. Use the independent check again rather than trusting visual similarity. This second pass trains selection: the learner must decide whether the same method still applies, adapt one step when a condition changes, and refuse the method when its trigger disappears.
Worked example 3: Correct city comparison
Task. Check: “Pine Town is larger than Cedar Town.”
Reasoning. The sentence compares one town with another town. Both visible subjects already belong to the same category.
Answer. Keep the sentence unchanged.
Independent check. Adding “that of” would wrongly substitute for a hidden singular feature that is not present.
Contrast-and-transfer pass. Keep the governing principle from “Correct city comparison”, but change one surface detail in the task: Check: “Pine Town is larger than Cedar Town.” Before recalculating or rewriting, name which evidence remains controlling and which detail has changed. The original conclusion—Keep the sentence unchanged.—may remain valid only if the changed detail does not alter the trigger, relationship or scope. Use the independent check again rather than trusting visual similarity. This second pass trains selection: the learner must decide whether the same method still applies, adapt one step when a condition changes, and refuse the method when its trigger disappears.
Worked example 4: Possessive score
Task. Improve: “Mina’s score was higher than the score of Ravi.”
Reasoning. The comparison is balanced but repetitive. A possessive can carry the omitted noun.
Answer. Mina’s score was higher than Ravi’s.
Independent check. Ravi’s expands clearly to Ravi’s score.
Contrast-and-transfer pass. Keep the governing principle from “Possessive score”, but change one surface detail in the task: Improve: “Mina’s score was higher than the score of Ravi.” Before recalculating or rewriting, name which evidence remains controlling and which detail has changed. The original conclusion—Mina’s score was higher than Ravi’s.—may remain valid only if the changed detail does not alter the trigger, relationship or scope. Use the independent check again rather than trusting visual similarity. This second pass trains selection: the learner must decide whether the same method still applies, adapt one step when a condition changes, and refuse the method when its trigger disappears.
Worked example 5: Uncountable quality
Task. Repair: “The quality of this paper is better than the recycled sample.”
Reasoning. Quality is compared incorrectly with a sample. Quality is singular or uncountable in this use.
Answer. The quality of this paper is better than that of the recycled sample.
Independent check. That expands to quality, not paper.
Contrast-and-transfer pass. Keep the governing principle from “Uncountable quality”, but change one surface detail in the task: Repair: “The quality of this paper is better than the recycled sample.” Before recalculating or rewriting, name which evidence remains controlling and which detail has changed. The original conclusion—The quality of this paper is better than that of the recycled sample.—may remain valid only if the changed detail does not alter the trigger, relationship or scope. Use the independent check again rather than trusting visual similarity. This second pass trains selection: the learner must decide whether the same method still applies, adapt one step when a condition changes, and refuse the method when its trigger disappears.
Worked example 6: Plural prices
Task. Repair: “The prices at Shop A are lower than Shop B.”
Reasoning. Prices are compared with a shop. The missing plural noun is prices.
Answer. The prices at Shop A are lower than those at Shop B.
Independent check. Here “those at” is natural because location, not ownership, identifies the prices.
Contrast-and-transfer pass. Keep the governing principle from “Plural prices”, but change one surface detail in the task: Repair: “The prices at Shop A are lower than Shop B.” Before recalculating or rewriting, name which evidence remains controlling and which detail has changed. The original conclusion—The prices at Shop A are lower than those at Shop B.—may remain valid only if the changed detail does not alter the trigger, relationship or scope. Use the independent check again rather than trusting visual similarity. This second pass trains selection: the learner must decide whether the same method still applies, adapt one step when a condition changes, and refuse the method when its trigger disappears.
Worked example 7: Weather comparison
Task. Repair: “The weather in June is wetter than December.”
Reasoning. Weather is compared with a month. Rebuild the weather in December.
Answer. The weather in June is wetter than that in December.
Independent check. The preposition in is retained because it identifies the period.
Contrast-and-transfer pass. Keep the governing principle from “Weather comparison”, but change one surface detail in the task: Repair: “The weather in June is wetter than December.” Before recalculating or rewriting, name which evidence remains controlling and which detail has changed. The original conclusion—The weather in June is wetter than that in December.—may remain valid only if the changed detail does not alter the trigger, relationship or scope. Use the independent check again rather than trusting visual similarity. This second pass trains selection: the learner must decide whether the same method still applies, adapt one step when a condition changes, and refuse the method when its trigger disappears.
Worked example 8: Ambiguous possessive
Task. Check: “Lina admires Mei’s drawings more than Jia’s.”
Reasoning. Jia’s can mean Jia’s drawings, but context must make that omission clear.
Answer. If ambiguity remains, write “more than Jia’s drawings” or state the intended comparison fully.
Independent check. Compression should not sacrifice recoverable meaning.
Contrast-and-transfer pass. Keep the governing principle from “Ambiguous possessive”, but change one surface detail in the task: Check: “Lina admires Mei’s drawings more than Jia’s.” Before recalculating or rewriting, name which evidence remains controlling and which detail has changed. The original conclusion—If ambiguity remains, write “more than Jia’s drawings” or state the intended comparison fully.—may remain valid only if the changed detail does not alter the trigger, relationship or scope. Use the independent check again rather than trusting visual similarity. This second pass trains selection: the learner must decide whether the same method still applies, adapt one step when a condition changes, and refuse the method when its trigger disappears.
The method lab: change one condition at a time
Collect ten comparison sentences and underline the exact head noun on each side. Sort them into balanced, faulty but repairable with that, faulty but repairable with those, and ambiguous.
Rewrite each faulty sentence first with full repetition, then with a substitute. The full version is the proof step; the compressed version is the editing step.
Change one singular head noun to a plural head noun and track every required change, including that to those and any verb agreement.
Compare a possessive repair with a that-of repair. Explain which is clearer, more natural and less ambiguous in the specific sentence.
Common misconceptions and targeted repairs
Misconception 1: A reader can guess, so the sentence is correct
What the learner may think. The learner accepts a city-versus-population mismatch because the intention feels obvious.
Why it fails. Grammar should encode the intended comparison, not force the reader to repair it.
Targeted repair. Name the head noun on both sides.
Misconception 2: Always add that of after than
What the learner may think. The learner changes correct subject comparisons.
Why it fails. The substitute is needed only when a repeated noun phrase is omitted.
Targeted repair. Expand the sentence before inserting anything.
Misconception 3: That and those are interchangeable
What the learner may think. The learner chooses by sound.
Why it fails. Number agreement still matters in substitution.
Targeted repair. Match singular or uncountable with that and plural with those.
Misconception 4: Of must always follow the substitute
What the learner may think. The learner writes awkward forms when at, in or another phrase is clearer.
Why it fails. The identifier depends on the original noun phrase.
Targeted repair. Preserve the natural preposition from the expanded form.
Misconception 5: Possessives compare people
What the learner may think. The learner reads “Ravi’s” as Ravi himself.
Why it fails. A possessive can stand for an understood owned noun.
Targeted repair. State the omitted noun during checking.
Misconception 6: Shorter is always better
What the learner may think. The learner compresses until the referent becomes ambiguous.
Why it fails. Economy is useful only when meaning remains recoverable.
Targeted repair. Restore the full noun when two readings remain possible.
Graded independent practice with explained answers
Attempt each item without looking ahead. Write the evidence or relationship before the final response. Early items check recognition; middle items require explanation; later items change the surface form so that copying a worked example is insufficient.
Practice 1: Singular substitute
Question. Repair: “The cost of Plan A is lower than Plan B.”
Explained answer. The cost of Plan A is lower than that of Plan B.
Why this earns trust. Cost is compared with cost.
Transfer variation. Close the answer, wait several minutes, and rebuild the reasoning with different names, values or wording while preserving the same decision. Start by stating the evidence that activates the method; then produce the response and a separate check. If the new surface detail changes the governing condition, explain why the earlier answer pattern must not be copied. The aim is not to repeat “The cost of Plan A is lower than that of Plan B.” from memory, but to recreate a justified answer from the new evidence.
Practice 2: Plural substitute
Question. Repair: “The books in Box A are heavier than Box B.”
Explained answer. The books in Box A are heavier than those in Box B.
Why this earns trust. Books is plural and the location phrase identifies the second group.
Transfer variation. Close the answer, wait several minutes, and rebuild the reasoning with different names, values or wording while preserving the same decision. Start by stating the evidence that activates the method; then produce the response and a separate check. If the new surface detail changes the governing condition, explain why the earlier answer pattern must not be copied. The aim is not to repeat “The books in Box A are heavier than those in Box B.” from memory, but to recreate a justified answer from the new evidence.
Practice 3: No change
Question. Check: “Box A is heavier than Box B.”
Explained answer. No change is needed.
Why this earns trust. One box is compared with another box.
Transfer variation. Close the answer, wait several minutes, and rebuild the reasoning with different names, values or wording while preserving the same decision. Start by stating the evidence that activates the method; then produce the response and a separate check. If the new surface detail changes the governing condition, explain why the earlier answer pattern must not be copied. The aim is not to repeat “No change is needed.” from memory, but to recreate a justified answer from the new evidence.
Practice 4: Possessive
Question. Compress: “Arun’s timing was faster than the timing of Joel.”
Explained answer. Arun’s timing was faster than Joel’s.
Why this earns trust. Joel’s clearly means Joel’s timing.
Transfer variation. Close the answer, wait several minutes, and rebuild the reasoning with different names, values or wording while preserving the same decision. Start by stating the evidence that activates the method; then produce the response and a separate check. If the new surface detail changes the governing condition, explain why the earlier answer pattern must not be copied. The aim is not to repeat “Arun’s timing was faster than Joel’s.” from memory, but to recreate a justified answer from the new evidence.
Practice 5: Uncountable noun
Question. Repair: “The air quality here is better than the city centre.”
Explained answer. The air quality here is better than that in the city centre.
Why this earns trust. Quality is compared with quality, and in identifies place.
Transfer variation. Close the answer, wait several minutes, and rebuild the reasoning with different names, values or wording while preserving the same decision. Start by stating the evidence that activates the method; then produce the response and a separate check. If the new surface detail changes the governing condition, explain why the earlier answer pattern must not be copied. The aim is not to repeat “The air quality here is better than that in the city centre.” from memory, but to recreate a justified answer from the new evidence.
Practice 6: Plural performance
Question. Repair: “The performances of Team X were stronger than Team Y.”
Explained answer. The performances of Team X were stronger than those of Team Y.
Why this earns trust. Those agrees with performances.
Transfer variation. Close the answer, wait several minutes, and rebuild the reasoning with different names, values or wording while preserving the same decision. Start by stating the evidence that activates the method; then produce the response and a separate check. If the new surface detail changes the governing condition, explain why the earlier answer pattern must not be copied. The aim is not to repeat “The performances of Team X were stronger than those of Team Y.” from memory, but to recreate a justified answer from the new evidence.
Practice 7: Direction check
Question. Does “A’s price is lower than B’s” compare A and B as objects?
Explained answer. No. The possessives stand for A’s price and B’s price.
Why this earns trust. The omitted head noun is recoverable.
Transfer variation. Close the answer, wait several minutes, and rebuild the reasoning with different names, values or wording while preserving the same decision. Start by stating the evidence that activates the method; then produce the response and a separate check. If the new surface detail changes the governing condition, explain why the earlier answer pattern must not be copied. The aim is not to repeat “No. The possessives stand for A’s price and B’s price.” from memory, but to recreate a justified answer from the new evidence.
Practice 8: Ambiguity
Question. Why might “I like Dana’s poems more than Lee’s” need context?
Explained answer. Lee’s may be clear as Lee’s poems, but the wider sentence could leave another owned noun possible.
Why this earns trust. Restore the noun if the referent is not secure.
Transfer variation. Close the answer, wait several minutes, and rebuild the reasoning with different names, values or wording while preserving the same decision. Start by stating the evidence that activates the method; then produce the response and a separate check. If the new surface detail changes the governing condition, explain why the earlier answer pattern must not be copied. The aim is not to repeat “Lee’s may be clear as Lee’s poems, but the wider sentence could leave another owned noun possible.” from memory, but to recreate a justified answer from the new evidence.
Practice 9: Expansion
Question. Expand “those of the second class” in a sentence about results.
Explained answer. It means “the results of the second class”.
Why this earns trust. Expansion verifies number and reference.
Transfer variation. Close the answer, wait several minutes, and rebuild the reasoning with different names, values or wording while preserving the same decision. Start by stating the evidence that activates the method; then produce the response and a separate check. If the new surface detail changes the governing condition, explain why the earlier answer pattern must not be copied. The aim is not to repeat “It means “the results of the second class”.” from memory, but to recreate a justified answer from the new evidence.
Practice 10: Routine
Question. State the four-step repair.
Explained answer. Underline the comparative, name the left item, match it on the right, then compress safely.
Why this earns trust. The repair begins with meaning rather than a memorised phrase.
Transfer variation. Close the answer, wait several minutes, and rebuild the reasoning with different names, values or wording while preserving the same decision. Start by stating the evidence that activates the method; then produce the response and a separate check. If the new surface detail changes the governing condition, explain why the earlier answer pattern must not be copied. The aim is not to repeat “Underline the comparative, name the left item, match it on the right, then compress safely.” from memory, but to recreate a justified answer from the new evidence.
A four-session mastery cycle
Session 1: construct. Read the mechanism once, cover it and write a three-line model containing the trigger, the operation and the check. Add one example and one near-miss. Compare only after the model is complete. If the operation is right but the trigger is missing, the knowledge is unsafe because it may be applied in the wrong place.
Session 2: discriminate. Mix six items: two that clearly require this method, two that tempt the method but violate a condition, and two that require another skill. For every item, write “use” or “do not use” before answering. Accuracy in method selection matters more than speed at this stage.
Session 3: explain. Give a complete answer to an imagined classmate. Include the smallest sufficient evidence, the mechanism and the independent check. Remove any sentence that merely repeats the question or adds an unsupported claim. A concise causal explanation is stronger than a longer collection of familiar words.
Session 4: perform. Attempt a timed mixed set without notes. Mark uncertain decisions, but continue. During review, classify each error as trigger, evidence, operation, scope, unit or check. Reattempt one changed version after a delay. Mastery is shown when the learner chooses and adapts the method without needing the original example beside it.
Delayed transfer: prove that the learning lasts
Transfer test 1: Report editing
After two days, repair comparisons involving cost, quality, rainfall and results.
Success criterion. Every repair identifies the shared head noun before choosing a substitute.
Transfer test 2: Singular-plural switch
Turn a that-of sentence into a those-of sentence by changing the comparison noun.
Success criterion. All agreement changes remain consistent.
Transfer test 3: Possessive challenge
Decide when a possessive is clearer than that of.
Success criterion. The learner can justify clarity rather than merely shorten.
Transfer test 4: Blank-page rule
Reconstruct compare like with like from memory.
Success criterion. The learner can expand every substitute back into a full noun phrase.
Examination control
1. Circle the comparative. Find the relationship before editing.
2. Underline both comparison items. Check that they belong to the same category.
3. Expand the missing noun. Prove the intended full meaning.
4. Choose that, those or a possessive. Preserve number and ownership.
5. Reread literally. Do not rely on the examiner guessing the intention.
Under time pressure, compress the method to comparative → left head noun → matching right noun → safe substitution → literal check. The compressed routine is useful only after the full reasoning is understood. If it produces uncertainty, expand the step instead of guessing.
A compact error log
Label errors as comparison item hidden, unlike categories compared, that/those number mismatch, identifier dropped, possessive ambiguous or unnecessary substitute inserted.
Retest by expanding every substitute into the full repeated noun phrase.
Notes for parents and tutors
Ask “What two things are actually being compared?” before offering a correction.
Let the learner write the repetitive full form first; compression comes only after accuracy.
Use real comparisons involving prices, travel times and temperatures without inventing numerical facts.
Praise a learner who leaves a correct comparison unchanged.
Frequently asked questions
What does “that of” replace?
It replaces a singular or uncountable noun phrase already stated on the left.
What does “those of” replace?
It replaces a plural noun phrase.
Must I always use of?
No. Preserve the natural identifier, such as in, at or a possessive, when that is clearer.
Can a possessive replace the repeated noun?
Yes, when the omitted owned noun is clear.
Why is “the population is larger than the city” faulty?
It compares a population with a city rather than with another population.
When is no substitute needed?
When both visible subjects already name comparable things.
Can I repeat the full noun?
Yes. Full repetition may be clearest, though a substitute often improves flow.
What is the safest check?
Expand the substitute and confirm both sides name the same kind of thing.
Next routes
Return to the complete volume directory to locate the series, use the original PSLE Learning Guide for the foundation route, and continue through PSLE English for verified subject guidance. The next useful task is a mixed set in which this idea is sometimes relevant and sometimes irrelevant; that is where the learner must choose a method rather than imitate one.