So Do I, Neither Can She: Short Agreement Responses with Auxiliaries

English can express agreement without repeating the full sentence. The key is to reuse the auxiliary that carries the original tense, aspect or modal meaning.

Core idea

Positive agreement uses So + auxiliary + subject: I like jazz — So do I; She is tired — So am I.

How the pattern works

Negative agreement uses Neither/Nor + auxiliary + subject: I don’t drive — Neither do I.

Meaning and context

Present Simple uses do/does, Past Simple did, while be, have and modal verbs repeat themselves.

A useful decision rule

Me too and Me neither are common informal alternatives, but auxiliary patterns are more flexible with different subjects and tenses.

Examples in context

• They have finished. — So have we.
• He can swim. — So can she.
• I can’t attend. — Neither can Maria.

Quick practice

1. Respond: I was late. (you too)
2. Respond: We have completed the task. (they too)

Suggested answers: So was I. / So have they.

Key takeaway

Match the auxiliary, then invert auxiliary and subject to create a concise grammatical echo.

Make the grammar usable

After you understand the explanation, create a contrast pair: one sentence where the target form is natural and one closely related sentence where a different form is needed. Then personalise one example. This moves the rule from recognition into retrieval and helps you notice the meaning difference in real speech and writing.