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A: Hi, Mike.
B: The air here is so dirty. I have a bad cough now.
A:
B: Look, Tom!
A: I can see much black smoke.
B: It’s from some factories. It can make the air very dirty.
A:
B: We can move those factories away from our city.
A: That’s a good idea.
| A．Is our city clean? |
| B．What can we do then? |
| C．What makes the air dirty? |
| D．What’s the matter? |
| E．Where is it from? |
| F．What can you see in the sky? |
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
