含有否定意义的副词或连词如hardly,never,not,not only,little等被前置时用部分倒装。例

　　词组hardly...when和no sooner...than都表示“刚刚…就”的意思。为了强调，这类句子也常常用倒装语序。例如：I had no sooner got there than it started raining heavily.变成：No sooner had I got there than it started raining heavily.

　　如果还是不明白的话我建议你去买本语法书来看，里面说的会更全面些…

　　no sooner than ...... equals to "as soon as..."

　　eg:No sooner was the frost off the ground than the work began.

　　地上的霜一消散，人们就开始工作了.

　　hardly when

　　Hardly had the thief seen the policeman when he ran away.

　　= Scarcely had the thief seen the policeman before he ran away. <before=when>

　　=No sooner had the thief seen the policeman than he ran away.

　　=As soon as the thief saw the policeman, he ran away.

　　=Upon seeing the policeman, the thief ran away. <upon=on>

　　<as soon as=the instant (when)=the moment (that)=immediately after=directly after=right after>

　　never, hardly, not only, nor, little, seldom, nowhere, not until, hardly…when, no sooner…than, by no means等表示否定或半否定意义的副词或词组开头的句子中，该句主谓要倒装。