Ellipsis and substitution

Avoid repetition with auxiliaries, so, not, one, ones and do so while keeping reference unambiguous.

When do we use it?

Choose a substitution form that matches the omitted verb phrase, noun or proposition.

Form

Use auxiliary ellipsis, do so, one/ones, and so/not after reporting verbs.

• She can speak French and so can I.
• I think so.
• The red one is cheaper.
• He promised to help and did so.

Key contrast

At C1, grammar choices shape emphasis, stance, information flow and register as well as basic correctness.

Common mistakes

• I think it so. → I think so.
• She can swim and I can so. → She can swim and so can I.

Remember

Avoid repetition with auxiliaries, so, not, one, ones and do so while keeping reference unambiguous.

Quick check

• Identify the focus, stance or relationship between clauses.
• Check inversion, complementation and reference carefully.
• Prefer the option that is both grammatical and appropriate for the register.