I( )on the door for ten minutes now without an answer.

admin2016-04-30  32

问题 I( )on the door for ten minutes now without an answer.

选项 A、was knocking
B、am knocking
C、knocking
D、have been knocking

答案D

解析 本题考查动词时态的用法。for ten minutes now作时间状语,动词应用完成时态。
转载请注明原文地址:https://kaotiyun.com/show/W8RO777K
0

随机试题
最新回复(0)