Hardly had he sat down when the telephone rang.语法要点

问题描述:

Hardly had he sat down when the telephone rang.语法要点
前面的hardly had he sat down,单词的位置杂这样别扭以及时态为什么要用完成时?

这个是倒装句
是固定的搭配
hardly had sb done
他刚坐下来的时候,电话铃响了
坐发生在响之前