______his number for an hour only to hear a busy signal, she became impatient and called the operator for assistance.
A.Dialing
B.Dialed
C.Having dialed
D.To dial
A.
A.Dialing
B.Dialed
C.Having
B.To
【参考答案】
C
本题考查非谓语动词,独立结构的逻辑主语与主句主语相同,所以用现在分词的完成时态。题意为,已经拨了一个小时他的号码都只是听到忙音,她不耐烦起来,打电话请接线员帮忙。