题干
The dog is _____the door. I can't see it.
A：in
B：on
C：behind
答案(点此获取答案解析）
C
The dog is _____the door. I can't see it.
A：in
B：on
C：behind
2SO3，改变下列条件，可以提高反应物中的活化分子百分数的是
