David knocked at the door for nearly half an hourMary opened it, unwilling.A. whenB. while

发布时间：2020-08-17 07:18:40

David knocked at the door for nearly half an hour    Mary opened it, unwilling.
A. when
B. while
C. until
D. before

网友回答

A. when
B. while
C. until
(答案→)D. before
解析：考查状语从句中的连词。句意：David敲门敲了将近半个小时Mary才不情愿地打开。状语从句中表示“过多久…才…”为before 的用法。选D。
以上问题属网友观点，不代表本站立场，仅供参考！