问题
选择题
The boy was so tired that he fell asleep _____________ his mother could take off his clothes．
A．before
B．after
C．while
D．where
答案
A
题目分析： 考查连词辨析。A．before在。。之前；B．after在。。之后；C．while然而；D．where 哪；句意：在他妈给他脱衣服之前这个男孩累得睡着了。根据文中提到The boy was so tired that he fell asleep可见他妈还没来得及给他脱衣服，故选A项。
考点 : 考查连词辨析