我国对空气治理的两类污染物重点是（）
A.SO2控制区和温室效应
B.酸雨控制区和臭氧层
C.SO2控制区和酸雨控制区
D.臭氧层和酸雨控制区
参考答案：C
American artist Jeremy Telford made a room with balloons．He got the from Bag End in the Lord of the Rings, which is a hole in the ground where a Hobbit（霍比特人）lives in the film．
A．inspiration
B．compliment
C．occupation
D．regulation
差速器有两种齿轮是（）和（）。
