You shouldn’t have the machines all the while. You ought to have them now and then.A. ru

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。