差动保护及重瓦斯保护同时动作变压器开关跳闸时，变压器不经内部检查和试验，（）投入运行。

A.不得

B.可试

C.可空载

D.可短时

—When did she get injured?

—It was at midnight     rain was pouring down.

A．where

B．that

C．what

D．when