For a long time we walked without saying ______ word and eventually Jack was the first to break ______ silence.
| A．the; a | B．a; the | C．a；/ | D．the；/ |
Expected noises are usually more _____ than unexpected ones of the like magnitude.
| A．manageable | B．controllable |
| C．tolerable | D．perceivable |
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 |