____ the boy was walking down the street, the UFO landed.
A.While B.After C. Before
—Mom, can I leave my homework for tomorrow?
—I’m afraid not. Don’t _________ what you can do today till tomorrow.
| A．put on | B．put down | C．put up | D．put off |
_______ you wait a few more minutes? It’ll be your turn soon.
| A．Must | B．Should | C．Could | D．Might |
—I called you at 4:00 yesterday afternoon, but no one answered.
—Sorry, I ______ with my friends at that time.
| A．swim | B．swam | C．will swim | D．was swimming |
You won’t feel happy at school ______ you get on well with your classmates.
| A．though | B．when | C．unless | D．because |
I have some problems with my English writing. Can you give me some________?
| A．advice | B．decisions | C．information | D．messages |