--How long at this job?
--Since 1990.
| A．were you employed | B．have you been employed |
| C．had you been employed | D．will you be employed |
Experts say walking is one of the best ways for a person to _____ healthy.
| A．preserve | B．stay | C．maintain | D．reserve |
Jack almost fell off the cliff, but managed to _____ until help came.
| A．keep on | B．catch on | C．count on | D．hang on |
The storm sweeping over this area now is sure to cause _____ of vegetables in the coming days.
| A．rarity | B．scarcity | C．invalidity | D．variety |
Don't _____ the news to the public until we give you the go-ahead (许可，准许).
| A．release | B．discard | C．relieve | D．retain |
If you _____ your demand, then maybe you will have more chance of getting what you want.
| A．conduct | B．dismiss | C．grant | D．moderate |