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English grammar

Ellipsis and Substitution (so, do, one)

Updated 27 Oct 2026 5 min read LingoLadder Editorial Team
Cover: Ellipsis and substitution — So do I, I think so, the red one
Short answer

Ellipsis leaves out words you can recover from context (She can swim but I can't); substitution swaps a short proform in for them (so, do so, one, not): So do I; I think so; the red one.

On this page10 sections · tap to jump
  1. 01The rule
  2. 02Forms
  3. 03Example sentences
  4. 04Common mistakes
  5. 05A short conversation
  6. 06Usage notes
  7. 07Compared with…
  8. 08Practice
  9. 09Quiz
  10. 10Recap cheat-sheet

Level: C1. Good English hates saying the same thing twice. Instead of I like coffee and she likes coffee, you drop or replace the repeat: I like coffee and so does she. Two tools do this job — ellipsis and substitution.

The rule

Ellipsis means leaving words out because the listener can fill them in from what came before. She can swim but I can’t — everyone understands can’t swim. Substitution means putting a short stand-in word in place of the longer phrase: so, do so, one, ones, not. Both avoid clumsy repetition, and both are a sign of natural, fluent English.

Auxiliary ellipsis is the most common. When a verb phrase would repeat, you keep only the auxiliary (the helping verb — be, have, do, can, will, should) and drop the rest: I haven’t finished, but she has (finished); Are you coming? I might (come); He works harder than she does. If the original has no auxiliary, do/does/did steps in: She sings better than I do.

So and neither for agreement use inversion. To agree with a positive statement, say So + auxiliary + subject: I’m tired. — So am I. To agree with a negative one, use Neither/Nor + auxiliary + subject: I don’t smoke. — Neither do I. The auxiliary matches the first speaker’s tense: I went. — So did I.

So and not after reporting verbs replace a whole that-clause. After think, hope, believe, expect, suppose, be afraid, guess, answer so for yes and not for no: Will it rain? — I think so / I hope not. Some verbs form the negative with don’t … so instead (I don’t think so), others with … not (I hope not, I’m afraid not).

One and ones replace a countable noun to avoid repeating it: I’ll take the red one; These shoes are nicer than those ones. Use one for singular, ones for plural, and only for countable nouns — never for uncountable ideas like advice, water or information.

Forms

Type Pattern Example
auxiliary ellipsis keep auxiliary, drop the rest I haven’t, but she has.
do-substitution do/does/did for no-auxiliary verbs He runs faster than I do.
so + agreement So + aux + subject I’m hungry. — So am I.
neither / nor Neither + aux + subject I can’t swim. — Neither can I.
so / not (clause) after think, hope, be afraid Is it open? — I think so.
do so / do it / do that replace a verb phrase He promised to call, and he did so.
one / ones replace a countable noun the blue one, the small ones
to-infinitive ellipsis keep to, drop the verb I’d love to.

Example sentences

  1. I like jazz. — So do I.
    Agreement with a positive: So + do + I.
  2. She is late. — So am I.
    The auxiliary matches 'is', so agree with 'am I'.
  3. I don't eat meat. — Neither do I.
    Agreement with a negative: Neither + do + I.
  4. He can't drive. — Nor can she.
    'Nor' works like 'neither' for negatives.
  5. I haven't finished, but she has.
    Auxiliary ellipsis: 'has' stands for 'has finished'.
  6. You can stay if you want to.
    To-infinitive ellipsis: 'to' stands for 'to stay'.
  7. Are you coming tonight? I might.
    The modal 'might' stands alone for 'might come'.
  8. She works harder than he does.
    'Does' substitutes for the repeated verb 'works'.
  9. Will the shop be open? I think so.
    'So' replaces the clause 'that the shop will be open'.
  10. Is it going to rain? I hope not.
    'Not' is the negative answer after 'hope'.
  11. Has he left already? I'm afraid so.
    'I'm afraid so' = yes, with regret.
  12. Do we have a meeting today? I don't think so.
    Negative formed with 'don't think so', not 'think not'.
  13. He said he would help, and he did so without complaint.
    'Did so' replaces the verb phrase 'helped'.
  14. I don't want this cup; give me the clean one.
    'One' replaces the countable noun 'cup'.
  15. These apples are fresh, but those ones are not.
    'Ones' replaces the plural countable noun 'apples'.
  16. My phone is older than yours, so I need a new one.
    'One' avoids repeating 'phone'.
  17. I promised to call her, but I forgot to.
    To-infinitive ellipsis: 'to' = 'to call her'.
  18. She passed the exam, and so did her brother.
    'So did' agrees with the past verb 'passed'.
  19. You might enjoy it; then again, you might not.
    'Might not' ellipts the repeated verb 'enjoy it'.
  20. Everyone was invited, and most people came.
    No substitute needed, but 'people' avoids repeating the subject idea naturally.

Common mistakes

  • ❌ I like it. — So I do. → ✅ I like it. — So do I. For agreement, invert the subject after the auxiliary: So do I. (So I do only confirms a fact already stated.)
  • ❌ Will it work? — I think yes. → ✅ Will it work? — I think so. English answers a yes/no idea with so, never yes after think/hope.
  • ❌ Do you need help? — I don’t think not. → ✅ Do you need help? — I don’t think so. With think, the negative is don’t think so, not think not.
  • ❌ I need some advice; can you give me one? → ✅ I need some advice; can you give me some? One replaces countable nouns only, never uncountable advice.
  • ❌ She can swim but I can’t swim. → ✅ She can swim but I can’t. Drop the repeated verb after the auxiliary; keeping it sounds heavy.
  • ❌ I’d love go. → ✅ I’d love to. Keep to when you ellipt the verb after it.

A short conversation

A: I can’t find my charger anywhere. B: Neither can I. I think I lost mine on the train. A: Shall we just buy new ones? B: I suppose so. The old ones were failing anyway.

Usage notes

  • Match the auxiliary. In so/neither answers, the auxiliary copies the first speaker’s verb: I have. — So have I. I didn’t. — Neither did I. With be, use be: I’m ready. — So am I.
  • So vs do so vs do it/that. So + auxiliary is for agreement. Do so is a formal substitute for a verb phrase (He was asked to sign, and he did so). Do it and do that are more concrete and common in speech.
  • Negative of reporting verbs. Think, suppose, believe, imagine, expect usually take don’t … so (I don’t suppose so). Hope, be afraid, guess, I’m sure take … not (I hope not, I’m afraid not).
  • One after the. You can say the big one but not usually a one; with an adjective, a big one is fine. After possessives and this/that, drop the noun directly: this one, mine, yours.
  • Do not over-omit. Ellipsis only works when the missing words are clearly recoverable. If the sentence becomes ambiguous, put the words back.

Compared with…

  • Advanced discourse markers such as mind you, having said that, as such, in any case organise and connect ideas across sentences; they signal the relationship between whole chunks of text. Ellipsis and substitution instead operate inside and between adjacent sentences to remove or replace repeated items. One manages the flow of an argument; the other trims the words. See Advanced Discourse Markers.

Recap card for the English ellipsis and substitution lesson showing so do I, I think so and one or ones

Quick recap before you practise.

Practice

Practice

Ellipsis and substitution practice

Try each one, then press Check. No sign-up, nothing is sent anywhere — it all runs in your browser.

1 Agree with 'I love this song.'
Show answer

So do I. — Agreement with a positive statement inverts: So do I.

Hint: the word that agrees with a negative

Show answer

Neither — Use Neither (or Nor) + auxiliary + subject: Neither can I.

3 Reorder into a natural answer meaning 'yes, probably'.

Show answer

I think so . — After 'think', the positive short answer is 'I think so'.

4 Match each prompt to its short answer.

  • Is it raining?
  • Did they win?
  • I'm exhausted.
  • I don't agree.
Show answer
  • Is it raining? → I hope not.
  • Did they win? → I think so.
  • I'm exhausted. → So am I.
  • I don't agree. → Neither do I.

Use so/not after reporting verbs and so/neither + inversion for agreement.

5 Which replaces the noun correctly in 'I don't like this bag; show me the leather ___.'?
Show answer

one — A singular countable noun is replaced by 'one': the leather one.

Hint: keep the auxiliary, make it negative

Show answer

haven't — Auxiliary ellipsis: keep 'have' and drop 'finished' — but I haven't.

Quiz

Check yourself

Ellipsis and substitution quiz

12 questions · pick an answer and you'll see straight away if it's right.

0/12 0 answered
  1. 1Agree with 'I am hungry.'
    Show answer

    So am I. — The auxiliary 'am' matches 'be', and the subject inverts: So am I.

  2. 2Agree with 'I don't like horror films.'
    Show answer

    Neither do I. — Negative agreement uses Neither + auxiliary + subject: Neither do I.

  3. 3Complete: 'Will the train be late? — I ___.'
    Show answer

    hope not — The negative answer after 'hope' is 'I hope not'.

  4. 4Which is the correct negative with 'think'?
    Show answer

    I don't think so. — 'Think' forms the negative short answer with 'don't think so'.

  5. 5Complete: 'She runs faster than I ___.'
    Show answer

    do — No auxiliary in the first clause, so 'do' substitutes: than I do.

  6. 6Choose the correct use of 'one'.
    Show answer

    This cup is dirty; pass the clean one. — 'One' replaces a countable noun (cup), not an uncountable noun.

  7. 7Complete with to-infinitive ellipsis: 'You can leave if you want ___.'
    Show answer

    to — Keep 'to' and drop the repeated verb: if you want to.

  8. 8Which sentence is WRONG?
    Show answer

    So me too do I. — 'So me too do I' mixes two patterns; use 'So do I' or 'Me too'.

  9. 9Replace the plural noun: 'These biscuits are stale, but those ___ are fresh.'
    Show answer

    ones — A plural countable noun is replaced by 'ones': those ones.

  10. 10Complete: 'He promised to apologise, and he ___ so at once.'
    Show answer

    did — 'Did so' substitutes for the verb phrase 'apologised'.

  11. Show answer

    did — Match the past verb 'passed' with 'did': So did I.

  12. 12Correct the error: 'Do you think it is true? — I think yes.'
    Show answer

    I think so. — English uses 'so', not 'yes', after 'think': I think so.

Recap cheat-sheet

Point Rule Example
agreement So / Neither + aux + subject So do I; Neither can I.
reporting verbs so = yes, not = no I think so; I hope not.
verb phrase keep the auxiliary I haven’t, but she has.
countable noun one / ones the red one; those ones.

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125 topics 125 ready now
A1 30 topics · 30 ready
  1. 01 Verb 'To Be' in the Present (am, is, are)
  2. 02 Subject Pronouns: I, You, He, She, It, We, They
  3. 03 Present Simple: Affirmative and the -s Ending
  4. 04 Present Simple: Negatives and Questions (do/does)
  5. 05 Articles: a / an and When to Use Each
  6. 06 The Definite Article 'The': When to Use It
  7. 07 Zero Article: When to Use No Article
  8. 08 Plural Nouns: Regular and Irregular Forms
  9. 09 This, That, These, Those (Demonstratives)
  10. 10 Possessive Adjectives: my, your, his, her
  11. 11 Possessive 's and s' (Showing Belonging)
  12. 12 There Is / There Are (Saying What Exists)
  13. 13 Have Got: Talking About Possession
  14. 14 Can and Can't for Ability
  15. 15 Present Continuous (am/is/are + -ing)
  16. 16 Imperatives: Giving Orders and Instructions
  17. 17 Adjectives: Position and Basic Use
  18. 18 Prepositions of Place: in, on, at
  19. 19 Prepositions of Time: in, on, at
  20. 20 Question Words: What, Where, When, Who, Why, How
  21. 21 How Much vs How Many
  22. 22 Countable and Uncountable Nouns
  23. 23 Some and Any: Which One to Use
  24. 24 Object Pronouns: me, you, him, her, us, them
  25. 25 Adverbs of Frequency and Their Position
  26. 26 Like, Love, Hate + -ing (Expressing Preferences)
  27. 27 Would Like: Polite Wants and Offers
  28. 28 Making Requests: Can, Could, May I
  29. 29 Past Simple of 'To Be' (was / were)
  30. 30 Let's and Shall We: Making Suggestions
A2 25 topics · 25 ready
  1. 31 Past Simple: Regular Verbs and -ed Spelling
  2. 32 Past Simple: Irregular Verbs (go, see, have)
  3. 33 Past Simple: Negatives and Questions (did)
  4. 34 Comparative Adjectives (bigger, more expensive)
  5. 35 Superlative Adjectives (the biggest, the most)
  6. 36 Going To: Plans and Predictions
  7. 37 Will: Predictions, Decisions and Offers
  8. 38 Present Continuous for Future Arrangements
  9. 39 Present Perfect for Experience (ever / never)
  10. 40 Present Perfect with just, already, yet
  11. 41 Present Perfect vs Past Simple
  12. 42 Have To and Don't Have To (Obligation)
  13. 43 Should and Shouldn't for Advice
  14. 44 Could: Past Ability and Polite Use
  15. 45 Much, Many, A Lot Of
  16. 46 A Few, A Little, Few, Little
  17. 47 Adverbs of Manner (quickly, well, hard)
  18. 48 Verb + -ing or Verb + to (Introduction)
  19. 49 Zero Conditional (Facts and Rules)
  20. 50 First Conditional (Real Future Possibility)
  21. 51 Prepositions of Movement (to, into, through)
  22. 52 Possessive Pronouns: mine, yours, hers
  23. 53 Past Continuous (was/were + -ing)
  24. 54 Too and Enough (Degree)
  25. 55 Order of Adjectives Before a Noun
B1 27 topics · 27 ready
  1. 56 Past Continuous vs Past Simple
  2. 57 Used To and Would for Past Habits
  3. 58 Present Perfect Continuous (have been -ing)
  4. 59 Present Perfect: Simple vs Continuous
  5. 60 Past Perfect (had + past participle)
  6. 61 Second Conditional (Unreal Present/Future)
  7. 62 Third Conditional (Unreal Past)
  8. 63 Reported Speech: Statements (Backshift)
  9. 64 Reported Questions
  10. 65 Reported Commands and Requests
  11. 66 Passive Voice: Present and Past Simple
  12. 67 Must and Mustn't (Strong Obligation)
  13. 68 May, Might, Could for Possibility
  14. 69 Defining Relative Clauses (who, which, that)
  15. 70 Non-Defining Relative Clauses (with commas)
  16. 71 Gerunds and Infinitives: Full Verb Patterns
  17. 72 Verbs Where -ing vs to Changes Meaning
  18. 73 Future Continuous (will be -ing)
  19. 74 So and Such (Emphasis)
  20. 75 As...As Comparisons (equality)
  21. 76 Question Tags (isn't it? do you?)
  22. 77 Phrasal Verbs: Separable and Inseparable
  23. 78 Linking Words: because, so, although, but
  24. 79 Infinitive of Purpose (to / in order to)
  25. 80 Indirect Questions (Can you tell me...)
  26. 81 Make, Let, Allow, Help (Causatives Intro)
  27. 82 Be Used To and Get Used To (+ -ing)
B2 25 topics · 25 ready
  1. 83 Narrative Tenses for Storytelling
  2. 84 Past Perfect Continuous (had been -ing)
  3. 85 Mixed Conditionals
  4. 86 Wish and If Only (Regrets and Wishes)
  5. 87 Wish/If Only + would (Complaints)
  6. 88 Passive Voice: All Tenses and Modals
  7. 89 Reporting Passive (It is said that / is said to)
  8. 90 Causative: Have/Get Something Done
  9. 91 Reduced Relative Clauses (Participles)
  10. 92 Modals of Deduction: Present and Past
  11. 93 Needn't Have vs Didn't Need To
  12. 94 Future Perfect (will have done)
  13. 95 Participle Clauses (-ing / -ed / having done)
  14. 96 Advanced Comparatives (far/much + er, the more)
  15. 97 Conditional Alternatives: unless, as long as, provided
  16. 98 Advanced Determiners: each, every, either, neither
  17. 99 Intensifiers and Adverbs of Degree
  18. 100 Advanced Contrast: despite, in spite of, however
  19. 101 Advanced Linkers: therefore, moreover, consequently
  20. 102 Advanced Article Use (generalisations, names)
  21. 103 Verb + Preposition and Adjective + Preposition
  22. 104 Relative Clauses: whose, where, when, quantifier + whom
  23. 105 Subject-Verb Agreement: Tricky Cases
  24. 106 Emphatic Do (I do like it)
  25. 107 Would for Past Habits (Formal Narrative)
C1 18 topics · 18 ready
  1. 108 Inversion with Negative Adverbials
  2. 109 Inversion in Conditionals (Had I known)
  3. 110 Cleft Sentences (It was... / What I need is...)
  4. 111 Fronting and Emphasis (Word Order)
  5. 112 Subjunctive and Mandative (I suggest he be)
  6. 113 Ellipsis and Substitution (so, do, one) You are here
  7. 114 Hedging and Cautious Language
  8. 115 Nominalisation (Academic Noun Style)
  9. 116 Advanced Discourse Markers (Spoken & Written)
  10. 117 Advanced Passive (passive + infinitive, get-passive)
  11. 118 Advanced Comparative Structures (no sooner...than)
  12. 119 Future in the Past (was going to / would)
  13. 120 Advanced Modals (may well, might as well, would rather)
  14. 121 Advanced Reported Speech (Reporting Verbs + Patterns)
  15. 122 Advanced and Idiomatic Phrasal Verbs
  16. 123 Collocation and Colligation (Natural Combinations)
  17. 124 Advanced Concession (much as, whatever, however + adj)
  18. 125 Absolute and Non-Finite Clauses (Formal)