barely / hardly / scarcely⋯when / before 及 no sooner+than 位于句首时，为固定的倒装结构，表示一件事紧接着另一件事发生，相 当于汉语的“一⋯⋯就⋯⋯”。

to speak when the audience interrupted him.

1. Hardly had he begun B) No sooner had he begun

C) Not until he began D) Scarcely did he begin 答案 A.

Scarcely had they settled themselves in their seats in the theatre

the curtain went up.

A) than B) when

C) before D) as soon as 答案：B.

例 2 试题本身有误，因为选项 B、C 都正确，也就是说，barely，hardly 和 scarcely 既可与 when 也可以与 before 搭配。no sooner 则必须和than 搭配。时态上，主句一般用过去完成时而从句（when, before 或than 引导）用过去沓，但表示一般情况时，主句也可用现在完成时，从句用一般现在时。例：

Scarcely has a forgigner set foot in the United States before

they ask him what he thinks of the country. 外国人刚去美国，他们就会问他对该国的看法。

No sooner had I left the house than it began to rain.我刚离开屋子天就下起雨来。

上述句中，若 barely, hardly, scarcely, no sooner 用于句中， 则不必倒装，例：

I had no sooner left the house than it began to rain.