题干
What I wanted to know was when and where the meeting______.
A：was holding
B：had held
C：was to hold
D：was to be held
答案(点此获取答案解析）
D
A：was holding
B：had held
C：was to hold
D：was to be held
4NO（g）+ 6H2O（g），下列叙述正确的是