Why is "do" sometimes put before a verb?

Question

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Use of “do” in affirmative statements

Why do people sometimes use the words "do" or "does" in affirmative sentences?

For example:

A: We know a guy!

B: We do know a guy!

Why doesn't B just say: "Yes, we know a guy"?

And in general, why the use of "do" in affirmative sentences?

score 4 · Accepted Answer · answered Sep 06 '11 at 18:57

4

Do in affirmative sentences is used to put an emphasis on the positive fact.

Person A: I've heard you don't have the piano anymore.
Person B: Oh, that's not true! I do have the piano!

answered Sep 06 '11 at 18:57

Frantisek

On a tangent, what is that "do" called? Is there a word for it? – Daniel Sep 06 '11 at 18:58
@dr65--It's generally do-support, but I'm not sure what "do" really is. – Sep 06 '11 at 19:21
@drm65, a modal verb? – Thursagen Sep 06 '11 at 21:24

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