He met many problems---he was going over his lessons.A. beforeB. as soon asC. sinceD.

发布时间：2020-08-21 12:42:04

He met many problems------ he was going over his lessons.
A. before
B. as soon as
C. since
D. while

网友回答

A. before
B. as soon as
C. since
(答案→)D. while
解析：考查连词。此句中主句中是一般过去时，而从句中是过去进行时，故用while。
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