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Boys and girls, today we will talk about “Then and now”. Before humans (人类) often ate raw meat (生肉). They didn’t cook their food. Now there are many things to help us cook delicious food. And the robots can help us cook, wash the dishes. Before there were many trees, green grass, blue sky and clean rivers. Now, there are more and more buildings. So many animals have no home. We also have no green grass, blue sky and clean rivers. We should help the earth (地球) from now.
1．What are they talking about? ( )| A．Then. | B．Then and now. | C．Now. |
| A．Yes, they were. | B．Yes, they did. | C．No, they didn’t. |
| A．The animals. | B．The robots. | C．The plants. |
| A．buildings | B．green hills | C．clear water |
| A．Help the earth. | B．See a doctor. | C．Take a deep breath. |
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
