Hardly

Hardly ______ the room when he told me the secret
A,I entered B.I had entered C .did I enter D .had I entered
及这种倒装句的结构

d
hardly分句中一般使用过去完成时,而when分句中使用过去时.
还有no sooner ……than
如果把hardly放在句首,则要求主谓实行部分倒装.如：
Hardly had we got home when it began to snow. 我们刚到家,就下起雪来.
Hardly had he arrived when she started complaining. 他刚到,她就开始抱怨.
再补充一点,这个句型中的hardly可以换成barely或scarcely.如：
Scarcely had he gone out when it began to rain. 他刚出门,就下雨了.
He had barely arrived when he had to leave again. 他刚到达,就不得不离开了.