can have done的初级英语语法

　　can have done

can have done初级英语语法 通常只用于否认句跟疑难句。用于否定句时表否定推断，揣测断定没做；用于疑难句时意为“难道真的做了吗”，表示怀疑。例如：

Can he have done such a foolish thing? (= Is it possible …?)

他会做这样的傻事吗？（表猜忌）

He can't have taken it home.

他不可能把它带回家了。（表不可能）

could have done

　　could have done 可用于确定句、疑问句跟否定句。用于肯定句既能够表现过去可能做而实际未做，有可惜、遗憾或委婉批评之意，也可以表示对从前动作的推测；用于否定句和疑问句的情况与can have done相同。初级英语语法例如：

You could have done better, but you didn't try your best.

你本可能做得更好，然而你不尽力而为。（表惋惜） CopyRight .com

This glass is cracked. Someone could have dropped it.

这个玻璃杯破了。可能是谁把它掉在地上了。（表揣摩从前）

Could he have left the work unfinished?

他会丢下工作不干了？（表猜疑）

He couldn't have checked out so early.

他不可能这么早就离开了。（表不可能）

　　留心：can't have done 的语气比 couldn't have done 要强一些。例如：

He can't have been to that town.

他基础不可能去过那座城市。（语气略强的初级英语语法）

The measurement couldn't have been wrong.

测量不可能出错了吧。（语气稍弱）

线话英语：www.linewow.com

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