Max’s legs are too long. When he walks _______ our desk, he often knocks our books_______ the floor.
We should play a part in ______ the earth.
The two students practice spoken English______ joining the English club.
You can’t get good grades______ you study hard.
-I can’t decide______. – You mean the red one or the blue one?
We need ______ and ______ for the milk shake.