Tom ____ into the house when no one ____

问题描述:

Tom ____ into the house when no one ____
Aslipped:was looking Bhad slipped:looked Cwas slipping :looked(附加理由)

选择A.理由:slip into 溜进来,动作瞬间完成,不能用过去完成时或者过去进行时.而后一个动作no one was looking 表示溜进来的当时 正好没人看到,故用进行时.懂了吧~