Compare:
Mei studies both English and Mathematics.
You can choose either the morning class or the afternoon class.
Neither the teacher nor the students were ready.
The experiment was not only expensive but also time-consuming.
Each sentence uses a pair of linking expressions.
The two parts work together:
both … and
either … or
neither … nor
not only … but also.
These are commonly called correlative conjunctions.
The central principle is:
Correlative conjunctions organise two matched alternatives or additions, so the grammar after the first half should normally be structurally parallel to the grammar after the second.
That means the topic is not only:
which connector should I use?
It is also:
what structures am I asking the reader to compare?
Both…and adds two members
Cambridge Grammar notes that:
both … and
creates a stronger explicit link than simple:
and.
Compare:
Mei studies English and Mathematics.
with:
Mei studies both English and Mathematics.
The second foregrounds:
the inclusion of both items.
Either…or presents alternatives
You may submit either a printed copy or a digital copy.
The pair sets up:
alternative A / alternative B.
Depending on context, the alternatives may be:
- exclusive;
- open;
- practical choices rather than strict logical XOR.
Grammar alone does not always tell us whether:
both options are impossible.
Context matters.
Neither…nor links two negative alternatives
Neither Mei nor Arun attended.
Meaning:
Mei did not attend;
Arun did not attend.
Cambridge notes that neither…nor can sound relatively formal in speech, while ordinary conversation may use:
Mei didn’t attend, and Arun didn’t either.
Not only…but also adds emphasis
The policy increased not only cost but also delay.
The second item is not simply added.
The structure tells the reader:
there is an additional point beyond the first one.
This makes:
not only … but also
useful for:
- emphasis;
- argument structure;
- rhetorical accumulation.
Parallelism is the hidden grammar underneath the pair
Good:
She enjoys both reading and writing.
After:
both
we have:
reading.
After:
and
we have:
writing.
Matched forms.
Now:
She enjoys both reading and to write.
The meaning is understandable.
The parallel structure is broken.
Correlative pairs should frame equivalent grammatical units
They can connect:
Nouns:
both English and Mathematics.
Adjectives:
both accurate and concise.
Verb phrases:
either revise the paragraph or rewrite the conclusion.
Clauses:
not only did the rain continue, but the wind also strengthened.
The important idea is:
match like with like.
Parallelism improves reader prediction
When the reader sees:
both + noun
they expect:
and + noun.
When they see:
either + verb phrase
they expect:
or + verb phrase.
Parallel grammar reduces processing load because the second structure is predictable.
“Not only” placement determines what is being paired
Compare:
Mei not only read the report but also annotated it.
Paired:
read / annotated.
Now:
Mei read not only the report but also the appendix.
Paired:
report / appendix.
Same words:
not only … but also.
Different scope.
This is why placement matters.
Scope errors can make the sentence logically crooked
Weak:
She not only likes reading but also Mathematics.
What is paired?
After:
not only
we have:
likes reading
but after:
but also
we have:
Mathematics.
The structures do not match.
Possible repair:
She likes not only reading but also Mathematics.
Or, if activities are intended:
She not only reads widely but also studies Mathematics intensively.
Either…or also needs structural balance
Good:
You can either revise the introduction or rewrite the conclusion.
Potentially awkward:
You can either revise the introduction or the conclusion needs rewriting.
The first alternative is:
verb phrase.
The second is:
full clause.
The pair no longer frames equivalent choices cleanly.
Neither…nor carries negative meaning without “not”
Correct:
Neither Mei nor Arun was present.
Do not normally add another negative:
Neither Mei nor Arun wasn’t present.
That creates:
double-negation confusion.
The correlative pair already supplies the negative relation.
Subject–verb agreement can become difficult
Consider:
Either the teacher or the students are presenting.
Now:
Either the students or the teacher is presenting.
In mixed-number either/or and neither/nor structures, standard usage often makes the verb agree with the nearer subject, though style guides frequently recommend rewriting if the result sounds awkward.
This is a good place to prioritise:
clarity over grammatical gymnastics.
Both…and normally creates plural agreement
Both Mei and Arun are ready.
Two coordinated subjects:
plural.
That pattern is much simpler than mixed-number:
either/or.
Neither can refer to exactly two alternatives
Cambridge points out that:
neither
is normally used for:
two.
For more than two possibilities, another structure may be clearer.
Students should avoid using:
neither of the three
when:
none of the three
is the intended standard form.
“Both…not” is often ambiguous
Compare:
Both students did not pass.
Does this mean:
neither passed?
Or:
not both passed?
Cambridge recommends clearer negative structures such as:
Neither student passed
for zero passers.
This connects correlative conjunctions to:
quantifier scope.
Not only at the front triggers inversion
Cambridge Grammar gives:
Not only was it raining, but the wind was also strong.
When:
not only
fronts the clause for emphasis, English uses:
subject–auxiliary inversion.
If there is no auxiliary:
do-support.
Example:
Not only did Mei finish the report, but she also checked every source.
This links correlative conjunctions to do-support
Base:
Mei finished the report.
Fronted emphatic structure:
Not only did Mei finish the report…
The auxiliary:
did
appears because inversion needs a finite auxiliary.
This is the same support system explained in the live do-support article.
Correlative punctuation is not “put a comma in the middle”
Weak:
Either the blue shirt, or the red sweater will work.
There is normally no comma simply because:
either
and:
or
form a pair.
Punctuation follows the larger syntax.
If a comma is required for another reason, use it.
Do not treat the correlative pair as a comma trigger by itself.
Not only…but also can connect whole clauses
Example:
Not only did the server fail, but the backup system also stopped responding.
Now there are two independent clauses.
The comma helps mark the clause boundary.
The punctuation comes from:
clause structure.
Not merely:
the correlative expression.
Correlative conjunctions can reduce repetitive writing
Weak:
The policy increased cost. The policy also increased delay.
More compact:
The policy increased both cost and delay.
The pair compresses:
shared grammatical material.
This improves:
- cohesion;
- economy;
- parallel reasoning.
But correlative pairs can become decorative
Students sometimes use:
not only … but also
because it sounds sophisticated.
If the two points are trivial or unrelated, the structure adds rhetorical weight without intellectual value.
Use it when:
the pairing itself matters.
Science example
The treatment affected both temperature and pressure.
Two dependent variables are grouped.
Now:
The error arose either during calibration or during data transfer.
Two alternative stages are proposed.
Correlative grammar maps directly onto experimental reasoning.
History example
The reform changed not only taxation but also military recruitment.
The writer signals:
the effects were broader than one domain.
Again:
paired grammar → paired historical claims.
Argumentative writing needs scope control
Sentence:
Schools should either ban phones or teach students to regulate them.
The pair presents:
two policy alternatives.
But is it really exhaustive?
Could there be:
a third option?
Grammar can create a false binary if the real-world choice is wider.
This is a critical-thinking issue.
Either/or can create false dilemmas
Claim:
Either students use AI for everything or they never use AI at all.
That framing ignores:
controlled intermediate use.
The grammar is correct.
The reasoning is poor.
Correlative conjunctions can therefore expose:
argument structure.
Neither/nor can strengthen categorical exclusion
Neither explanation fits the evidence.
This is stronger than:
Both explanations have problems.
The first excludes both alternatives.
The second merely criticises them.
Word choice changes logical force.
Both…and can accidentally imply completeness
Sentence:
The problem affects both teachers and students.
Does that imply:
only those two groups?
Not necessarily.
But the paired structure foregrounds them as the relevant set.
Writers should check whether important third groups are being omitted.
A practical parallelism test
Locate the two halves:
both X and Y.
Then label X and Y.
Are they both:
- nouns?
- adjectives?
- verb phrases?
- clauses?
If not:
rewrite for structural balance.
A practical scope test
Sentence:
Mei not only checked the introduction but also the conclusion.
Ask:
What exactly is paired?
If the intended pair is:
introduction / conclusion,
better:
Mei checked not only the introduction but also the conclusion.
Move the first correlative marker to the start of the material being paired.
A practical agreement test
With:
either/or
or:
neither/nor,
identify the two subject alternatives.
If their numbers differ:
consider proximity agreement;
then ask:
would rewriting remove awkwardness?
Often the cleanest answer is:
rewrite.
Parent-friendly practice
Give:
Mei likes swimming.
and:
Mei likes cycling.
Ask the child to combine them:
Mei likes both swimming and cycling.
Then intentionally break it:
Mei likes both swimming and to cycle.
Ask:
Why does the second feel uneven?
The child discovers:
parallel structure.
Teacher-friendly diagnosis
Pairing error: both/as well as or either/and mixed incorrectly.
Parallelism failure: noun paired with clause, -ing form with infinitive, adjective with noun.
Scope error: first marker placed too early or too late, changing what is paired.
Agreement overload: mixed singular/plural alternatives produce awkward verb choice.
Punctuation myth: comma inserted merely because a correlative pair appears.
False-binary reasoning: either/or presents two choices as exhaustive without evidence.
Singapore relevance
Students use correlative conjunctions in:
- argumentative writing;
- Science explanations;
- History essays;
- oral discussion;
- situational writing;
- formal presentations.
The useful target is not:
use more not only…but also.
It is:
pair genuinely parallel ideas and make the logical relationship accurate.
Hilary Mantel as a high-level literary lens
Balance in a sentence is not ornamental symmetry.
It tells the reader:
these two things belong in the same frame.
The transferable lesson is:
parallel grammar creates parallel attention.
The value is controlled structure, not imitation.
AI and correlative conjunctions
AI systems often produce fluent but unbalanced:
not only X but also Y
structures.
They can also change:
either/or
into a false binary.
A useful public audit prompt is:
Identify every correlative pair. Check that the two framed elements are grammatically parallel, that scope is aligned, that subject–verb agreement is natural, and that either/or does not falsely imply exhaustive alternatives.
The larger lesson
Correlative conjunctions are paired grammar.
Both…and:
adds two members.
Either…or:
frames alternatives.
Neither…nor:
rejects both alternatives.
Not only…but also:
adds a second point with emphasis.
But the real skill lies underneath:
the two halves must line up in grammar and in thought.
That is why correlative conjunctions are not merely connector vocabulary.
They are parallel reasoning made visible.
Connections eduKateAI can learn
both X and Y → additive pairing
either X or Y → alternative pairing
neither X nor Y → negative pairing
not only X but also Y → emphatic additive pairing
X/Y → should be structurally parallel
fronted not only → inversion/do-support
either/or → check false-binary risk
The public principle is that correlative conjunctions create paired grammatical frames whose elements should be structurally parallel and logically comparable.
Related eduKateSG resources
- Coordination and Subordination in English
- Do-Support in English
- Fronting and Inversion
- Subject–Verb Agreement in English
- Each, Every and All in English
Research basis
This article follows current Cambridge Grammar guidance on two-part conjunctions, both…and, neither…nor and not only…but also, including inversion after fronted not only. See https://dictionary.cambridge.org/grammar/british-grammar/subordinating-conjunctions, https://dictionary.cambridge.org/grammar/british-grammar/both, https://dictionary.cambridge.org/grammar/british-grammar/neither-nor, and https://dictionary.cambridge.org/us/grammar/british-grammar/not-only.