二、句型剖析

　　1.only引导的状语位于句首引起的倒装句

　　【典型例句】

　　Only by shouting at the top of his voice was he able to make himself heard.

　　只有他大声叫喊,才能让别人听到。

　　Only in this way can we achieve what we want.

　　只有用这种方法我们才能完成想做的事情。

　　Only in each afternoon does the university library open.

　　只有每天的下午大学图书室才开门。

　　【要点归纳】

　　只有only修饰的时间状语、条件状语和方式状语置于句首以示强调时,该句才用部分倒装语序。如果only修饰主语时,语序不变。

　　2."情态动词+have done"表示推测

　　【典型例句】

　　The windows look bright and clean today.Someone must have cleaned them.

　　窗户今天看起来明亮清洁，肯定有人擦过它们。

　　He said she might have missed the train.

　　他说她可能没有坐上火车。

　　You could have succeeded.

你本能够成功。