2013年职称英语考试语法指导：情态动词2

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2013年职称英语考试语法指导：情态动词2
' j( \. @. E$ K2 s1 y8 V情态动词+行为动词完成式
　　情态动词+行为动词完成式即“情态动词+ have + v-ed分词”，表示对过去行为或动作进行推测、评论或判断。
3 U6 p/ ]/ y( l4 X% I( R; i- D9 Q! Q( M　　1. must have v-ed 外语学习网
" b% l* o  F8 v) a! D4 i　　must have v-ed 表示推测过去某事“一定”发生了。其否定形式为：can't / couldn't have v-ed， 表示过去不可能发生某事。例如：
　　1）Since the ditch is full of water， it must have rained last night.
　　2）You couldn't have met my grandmother. She died before you were born.
　　2. could have v-ed
1 D# h# B" o6 k: Q　　could have v-ed 表示推测过去某动作“很可能”发生了。例如：
　　1）“The dictionary has disappeared. Who could have taken it？”
　　2）“Tom could have taken it. He was alone yesterday.”