There is a mistake in each sentence.correct the mistakes 1,actors may learn a lot of dialogues by heart 2.your glass is empty.must i refill it? 3.would i introduce mr.brown to you? 4,my sister can to play a few musical instruments. 5.some years ago i didn`t can speak english.

1. Actors may learn a lot of dialogues by heart.
Actors can learn a lot of dialogues by heart.

2. Your glass is empty. Must I refill it?
Your glass is empty? Shall I refill it?

3. Would I introduce Mr. Brown to you?
May I introduce Mr. Brown to you?

4. My sister can to play a few musical instruments.
My sister can play a few musical instruments.

5. Some years ago I didn't can speak English.
Some years ago I couldn't speak English.