In order to attract more customers,many supermarkets usually sell their goods at a good at weekends.
| A．discount | B．profit | C．bargain | D．cost |
When Mary came, I _____ on the piano.
| A．is playing | B．plays | C．was playing | D．played |
Cars, buses and bikes ________ stop when the traffic lights turn red.
| A．can | B．may | C．must | D．need |
_______ we got to the station, the train had left already.
| A．If | B．Unless | C．Since | D．When |
Tom kept quiet about the accident _____ lose his job.
| A．in not order to | B．in order not to |
| C．in order to not | D．not in order to |
He is very old, ______ he still works very hard.
| A．but | B．if | C．when | D．as |