They're in different ________.
A. class B. school C. schools
We shouldn't make noise here. It means “________”．
A. Keep off the grass
B. Keep quiet
C. Don't touch
The sign means you shouldn't ______ photos
here.
A. take B. talk C. taking
Ben，open the window please. ______ close it.
A. Don't B. Aren't C. Not
It's time ________ some cakes.
A. to B. for C. for have