题干
We have done much to protect the environment. So the river is getting than before.
A：dirtier
B：dirty
C：cleaner
D：clean
答案(点此获取答案解析）
C
We have done much to protect the environment. So the river is getting than before.
A：dirtier
B：dirty
C：cleaner
D：clean
2NH3(正反应为放热反应)达到平衡后，下列选项中三种方法都能使平衡向正反应方向移动的是（ ）