Question

1. Don't laugh.

2. Do not laugh.
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Where do we have to use #1 or #2?
In everyday speech, we use #1. In a formal writing, do we have to use #2?

3. I don't like dancing in public.
4. I do not like dancing in public.
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What about this pair? Is #4 stronger than #3 in meaning? Do we have to use #4 in a formal writing?

Answer 1

Yes, 1 and 3 are mostly used in casual conversation (which is most of the time!). The other two (no contractions) are mostly used in formal writing OR for emphasizing the word "not." (I do not like ... )