反应A₂（g）+B₂（g）=2AB的速率方程V=kC（A₂）·C（B₂）时，可以得出此反应为（）。

A.基元反应

B.非基元反应

C.无法肯定是否为基元反应

D.是一个快反应

根据所给提示，完成句子。每空一词，含缩略词。

小题1:He did his homework last night. (改为否定句)

He __________ __________ his homework last night.

小题2:The kid is playing the piano at the school music club. (对划线部分提问)

__________ is the kid __________ the piano?

小题3:Visitors love this city because it has historical sights and delicious food. (改为同义句)

Visitors love this city __________ _________ its historical sights and delicious food.

小题4:他两个月没有收到他儿子的信了。(完成译句)

He hasn’t ________ ________ his son for two months.