–Our classroom _________ twice a day. So it is very clean.–It is important for us to do this.
—Hi, Mike, I’ve got a present __________ you. —Oh, it’s really beautiful. Thank you very much.
The girl is at school. __________ is busy with her work.
The teacher asked me ____.
Some polluting factories _____by Beijing government soon in a few months.
My parents will buy a piano for me if I _____ good grades in the tests.