He____ up and down the balcony all the time before the stranger c_英语解答

He____ up and down the balcony all the time before the stranger came.
A.had paced
B.had been paced
C.had been pacing
D.was pacing

人气：348 ℃　时间：2020-05-16 06:33:53

解答

C 表示在陌生人来之前,过去的过去要用过去完成时,表示他一直在走个不停要用进行时,一组合就是过去完成进行时．