It was _______ back home after the experiment.

A．not until midnight did he go

B．until midnight that he didn’t go

C．not until midnight that he went

D．until midnight when he didn’t go

青藏交直流联网工程包括（）。

A.西北750kV输变电工程

B.格尔木－拉萨400kV直流输电工程

C.藏中220kV输变电工程

D.藏中110kV输变电工程