The environment is becoming worse and worse. I think we should do something to ____ people ____ cutting the trees in order to protect the earth.
---Why don't you go to the lecture-room and listen to the talk? ---I hear there isn't ________in it.
There are books on the shelf. And them is about three hundred.
Do you know what in the room at the moment?
---When shall we leave for Shanghai? ---We won’t we have visited all the places of interest in Nanjing.
---How many students have visited Yangzhou Museum? ---____