职称英语考试句型语序：从句类型(1)

时间状语从句

　　I) when，while和as

　　He entered the room when (while, as) the meeting was going on.

　　when 通常指一时的动作或状态，可表示从句动作与主句动作同时发生，或先于主句动作;while常用来引导两个同时进行的持续时间较长的动作;as常用来引导两个动作紧接着发生，强调“同一时间”或“一前一后”。

　　When I meet the right chance, I will try my best.

　　While the teacher explained the text, the students listened attentively and took notes

　　He sang songs as he was taking a bath.

　　As spring warms the earth, all flowers begin to bloom.

　　注：when有时作并列连词意为“正在这时”、“突然”，在句末，不能位于句首。从句的谓语动词常用一般过去时，主句通常用过去进行时、过去完成时或be about to结构等。

　　She was about to leave when Mark arrived so she stayed a little longer.

　　He had been walking under the trees when an apple fell down. 考试用书

　　Ⅱ) as soon as, hardly (scarcely, barely) … when… , no sooner …than… 等引导的时间状语从句，意为“ 一… 就 …”

　　Jack had scarcely /hardly seen me when he left the room.

　　The spy had no sooner returned home than he was told to go to another country.

　　那个间谍一踏进国门就奉命要去他国。

　　注： 在no sooner … than, hardly … when …引导的时间状语从句中，若把no sooner, hardly, scarcely, barely 放在句首，则要用倒装结构。

　　No sooner had he heard the news than he fainted.

　　Scarcely had he entered the room when the telephone rang.