题目内容：
Pollution levels are lower__________A When you get up
B Where you stand while waiting to cross a road
C Where you walk
D Where you sit on a bus and how you travel
E When you go to bed
F When pollution levels rise and fall
参考答案：
答案解析：
单选题：Pollution levels are lower__________A When you get upB Where
- 题目分类：综合类
- 题目类型：单选题
- 查看权限：VIP
A When you get up
B Where you stand while waiting to cross a road
C Where you walk
D Where you sit on a bus and how you travel
E When you go to bed
F When pollution levels rise and fall