题干
-- Where's Mr Yu, do you know?
-- Well, it's hard to say. But I heard him loudly here just now.
A：was reading
B：reading
C：had read
D：to read
答案(点此获取答案解析）
B
-- Where's Mr Yu, do you know?
-- Well, it's hard to say. But I heard him loudly here just now.
A：was reading
B：reading
C：had read
D：to read
在体积不变的密闭容器中反应，达到平衡状态的标志是：
的同时生成2nmol
的物质的量浓度变化表示的反应速率比为2：2：1的状态