Ⅰ. 三者在意義上基本相同，都有“一……就……”，“剛……就……”，但它們各有其特點。

　　Ⅱ. as soon as 最為普通，位置靈活，可在主句前，也可在其后。且可用作多種時態。如：

　　① As soon as I went in , Kate let out a cry of surprise. 我一進去，凱特就驚訝地叫了一聲。

　　② I’ll tell him as soon as he comes back.

　　Ⅲ. hardly… when…的主句通常 用過去完成時，從句用一般過去時，when有時還可換成before.如：

　　① He had hardly finished his homework when the light went out. 他剛寫完作業燈就滅了。

　　② Hardly had I come back when they began quarrelling.我一回來他們就開始吵了起來。(hardly 提前時，句子需要倒裝。)

　　Ⅳ. no sooner…than…句型中， no sooner一般只置于句首，所以主句有倒裝形式。如：

　　No sooner had I known the news than I telephoned my mother. 我剛知道這個消息就打電話告訴了媽媽。