题干
-I give up．It’s too hard．
-Really? I______you could make it through．
A：think
B：thought
C：have thought
D：am thinking
答案(点此获取答案解析）
B
A：think
B：thought
C：have thought
D：am thinking
2NH3，3 min后测得密闭容器内的压强是起始时的0．9倍，在此时间内v(H2)是( )