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With the improvement of our living standard, more and more people can afford cars. However, the smoke from the cars makes the air dirty. Air pollution has become a serious problem around the world. That’s very dangerous for us and animals.
We should do something to make the air clean again. But what can we do? We can do some small things in our daily life. For example, we can go to school by bike or on foot. That can reduce the smoke. Trees can clean the air. So we should plant more trees and stop cutting down so many trees. Why not have a try?
1．With the improvement of our living standard, more and more people can _________。( )| A．buy elevators | B．buy bikes | C．buy cars |
| A．The dust | B．The smoke | C．The wind |
| A．By planting more trees. |
| B．By riding a bike or walking to school. |
| C．Both A and B. |
| A．walking to school is very important |
| B．protecting the environment is very important |
| C．cars are very important |
同类型试题
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
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
