题干
You can have a good view of Nanjing at the top of Zijin Mountain ______ a clear day.
A：at
B：on
C：in
D：for
答案(点此获取答案解析）
B
You can have a good view of Nanjing at the top of Zijin Mountain ______ a clear day.
A：at
B：on
C：in
D：for
2NO+O2 在体积不变密闭容器中反应，达到平衡状态的标志是：