题干
The employee to impress the company with his cleverness and promptness.
A：set about
B：set out
C：set off
D：set u
答案(点此获取答案解析）
B
A：set about
B：set out
C：set off
D：set u
CO2（g）＋H2（g），反应放出热量。反应中CO2的浓度随时间变化的情况如下图所示。