问题补充:
You shouldn’t have the machines all the while. You ought to have them now and then.
A. run; repair
B. running; repairing
C. run; repaired
D. running; repaired
答案:
A. run; repair
B. running; repairing
C. run; repaired
(答案→)D. running; repaired
解析:考查非谓语动词。句意:你不应该让机器一直运转。你应该不时地把他们修理一下。结合语境可前正在进行的动作伴随性动作,下文描述的是被动动作,故选D。