1. -What can we do to keep our city clean?
- We can take the___________ to school.
![](http://static.xuejinqu.com/qimg/7f2/7f2852a89fdfafc99744a443fbf49ddc.png)
2. -What can we do to keep the air clean?
- We can ___________.
![](http://static.xuejinqu.com/qimg/0a1/0a18a8944df0358c903853ad2cd51ff9.png)
3. -What can we do to keep our city clean?
- We can move some ___________ away from our city.
![](http://static.xuejinqu.com/qimg/2d3/2d340cb1273d209f066181dfafdb3d98.png)
4. -What makes our city dirty?
- ___________ from cars makes the air dirty.
![](http://static.xuejinqu.com/qimg/64f/64fad8fe5178c1bc24b00fd424c8e2ec.png)
5. -What can we do to keep the river clean?
- We can put the rubbish in the ___________.
![](http://static.xuejinqu.com/qimg/07c/07c752260fb1ecbd897a394251bec794.png)
![](http://static.xuejinqu.com/images/y-prise.png)
同类型试题
![](http://static.xuejinqu.com/images/medal.png)
y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
![](http://static.xuejinqu.com/images/avatar.png)
![](http://static.xuejinqu.com/images/avatar.png)
y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
![](http://static.xuejinqu.com/images/avatar.png)
![](http://static.xuejinqu.com/images/avatar.png)