Lesson

So and not as substitutes for clauses

Clause substitution

≈ 20 min 8 block(s)

Text

So and not as substitutes for clauses

This lesson explains how to avoid repeating a whole clause by using short substitute structures. Native speakers often replace a repeated clause with a compact expression using so, neither, either or an auxiliary + not. These substitutes keep sentences concise and natural in conversation and business English.

  • Use 'so' + auxiliary + subject to agree with a positive clause (e.g., So do I).
  • Use 'neither' + auxiliary + subject (or auxiliary + not + either) to agree with a negative clause.
  • Do not forget inversion after 'so' and 'neither' (auxiliary before the subject).

Table

Substituting full clauses with short forms

Full clause Substitute clause Example
She completed the report. So did I. She completed the report, and so did I.
They will attend the meeting. So will we. They will attend the meeting, and so will we.
He didn't approve the budget. Neither did I. He didn't approve the budget, and neither did I.
She can't join the call. I can't either. She can't join the call, and I can't either.

Tip

Key rule: structure and inversion

Remember two important points when substituting clauses:

  • For positive agreement use: So + auxiliary/modal + subject (So do I; So have they; So can she).
  • For negative agreement use: Neither + auxiliary + subject OR auxiliary + not + either (Neither did I; I didn't either).
  • After 'so' and 'neither' you must invert auxiliary and subject (auxiliary comes before subject).

If there is no auxiliary in the original clause, use a suitable dummy auxiliary (do/does/did).

Example

Examples in context

Our team met the deadline, and so did the New York office.

The CEO approved the plan, and so will the board next week.

They didn't receive the invoice, and neither did we.

She can't attend the webinar, and I can't either.

Tip

Common mistakes to avoid

Watch out for these universal errors when using substitutes:

  • Omitting the auxiliary: Incorrect: 'She finished the report, and so I.' Correct: 'So did I.'
  • Wrong word order (no inversion): Incorrect: 'So I did.' Correct: 'So did I.'
  • Using 'so' for negative agreement: Incorrect: 'He didn't come, so did I.' Use 'Neither did I' or 'I didn't either.'
  • Mixing forms: Don't combine 'neither' with 'either' in the same short response (avoid 'Neither did I either').

Always check whether the original clause is positive or negative before choosing 'so', 'neither' or 'either'.

Quiz

Choose the correct sentence:

Hint: Check inversion: auxiliary before subject after 'so'.

Quiz

Complete: They will attend the meeting, and _____

Hint: Use 'so' with the correct auxiliary and subject; remember inversion.

Quiz

Choose the correct response to a negative statement: "I didn't receive the invoice."

Hint: Think about negative agreement forms (neither / ... either).

Key Points

GrammarPoint

so (agreement pro-form)

expression CEFR B1 //soʊ//

A pro-form used with an auxiliary to agree with a positive clause (So do I).

The team reached its target, and so did the sales department.

GrammarPoint

neither

conjunction/particle CEFR B1 //ˈniːðər//

Used to agree with a negative clause: Neither + auxiliary + subject (Neither did I).

He didn't sign the contract, and neither did the partner company.

GrammarPoint

either (in negative responses)

adverb CEFR B1 //ˈiːðər//

Used after a negative clause to agree without inversion: I didn't either.

We couldn't access the server, and I couldn't either.

Vocabulary

auxiliary

noun CEFR B2 //ɔːɡˈzɪljəri//

A helping verb used to form questions, negatives, or to create substitutes (do, have, will, can, etc.).

Do is the auxiliary we use when there is no other auxiliary in the sentence.

GrammarPoint

inversion

noun CEFR B2 //ɪnˈvɜːrʒən//

The switching of auxiliary and subject order (auxiliary before subject) used after 'so' and 'neither' substitutions.

Correct inversion: 'So did we.' Incorrect: 'So we did.'

Vocabulary

substitute (clause substitution)

noun/verb CEFR B2 //səbˈstɪtjuːt//

A shorter expression that replaces a repeated clause to avoid redundancy.

Use a substitute to avoid repeating long clauses in business emails.