Ellipsis and substitution

Rules

• Rule 1: so and not replace a whole clause

  After think, hope, expect, suppose, guess, be afraid, use so (positive) or not (negative) instead of a whole clause. With think, the natural negative is I don't think so. With hope and be afraid, use not.

  Pattern: I think / hope / expect so · I hope / I'm afraid not · I don't think so

  Example: “Is the test on Friday?” “I think so.”

  Example: “Is there any cake left?” “I'm afraid not.”

• Rule 2: one / ones replace countable nouns

  Use one (singular) and ones (plural) to avoid repeating a countable noun. Not with uncountable nouns like water or bread.

  Pattern: a / the / adjective + one · adjective + ones

  Example: My pencil is broken. Can I borrow one?

  Example: I like the striped socks more than the plain ones.

• Rule 3: So / Neither / Nor + auxiliary + subject

  To agree: positive → So + auxiliary + subject; negative → Neither / Nor + auxiliary + subject. The auxiliary must match the first sentence.

  Pattern: So + auxiliary + subject · Neither / Nor + auxiliary + subject

  Example: “I've read every book in this series.” “So have I!”

  Example: “I didn't hear the bell.” “Neither did I.”

• Rule 4: Auxiliaries, to and do so

  Keep just the auxiliary instead of repeating the verb phrase. After verbs like want, love, try, keep just to. In formal English, do so replaces a whole action.

  Pattern: … auxiliary. · … want / love / try to. · … do so

  Example: Some of us finished the puzzle, but others didn't.

  Example: Visitors may take photos, but they must not do so with a flash.

Common mistakes

• “Will it rain?” “I hope no.” → “Will it rain?” “I hope not.”

  Use not, not no.

• “I love chess.” “So am I.” → “I love chess.” “So do I.”

  love → auxiliary do.

• “I think it.” → “I think so.”

  Replace the clause with so.