11.30 過去將來完成時(shí)

形式
should / would have done sth. 　　

用法 　　
1、 過去將來完成時(shí)表示在過去將來某一時(shí)間以前發(fā)生的動作，并往往會對過去將來某一時(shí)間產(chǎn)生影響。
I thought you'd have left by this time. 我想這會兒你已經(jīng)走了。 　　
He told them he would have finished it by 8 o'clock. 他告訴他們他會在8點(diǎn)以前干完。 　　
I guessed that Helen would have told her something. 我猜海倫會告訴她一些情況的。 　　

2、 過去將來完成時(shí)還常用在虛擬語氣中，表示與過去的事實(shí)相反。