What do you usually do____ Sunday mornings. A. in B. at C. on
––Could I sweep the floor later? I want to do my homework first. ––Yes, _______.
Beckham stopped playing soccer ______ his bad leg.
You should take more exercise. It’s good ______ your health.
It’s important for Jim ______ the piano well, if he wants to be a musician.
If you want to be a ______, you should study math hard.