--Mr. Li will check our homework this afternoon. ______ you _______ it?--Not yet. I'm doing it right now.
Boys, don’t stop-please _______ with your work.
- Can you help me clean the room? - OK, _______ I have to wash the clothes first.
Everybody knows that blind people shouldn’t _______.
I think _______ is meaningful to help other people.
Great changes _______ in our country since 1990.