You’d better put a cloth over the salad to the flies for the sake of health.A. keep offB.

问题补充：

You’d better put a cloth over the salad to the flies for the sake of health.

A. keep off

B. keep out

C. help out

D. hold out

答案：

(答案→)A. keep off

B. keep out

C. help out

D. hold out

解析：句意: 为了健康起见，你最好用布盖上色拉，不让苍蝇靠近。keep off （to stop something touching or harming sbor sth）避开；不靠近，符合题意。keep out（to not go in a place, or to stop sb or sth from going into a place）关在门外；不准入内；help out 帮助某人摆脱困境等；hold out坚持；维持。