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Do you know something about our Earth (地球)? There are all kinds of trees, flowers and grass on our Earth. There are all kinds of wild animals living together with us. We should keep our Earth beautiful. But sometimes we do bad things to it. We waste too much water. We cut down too many trees. We hunt too many wild animals for our food or clothes… We shouldn’t do these things. We should save our Earth because we have only one Earth.
1．Sometimes we do bad things to our Earth. （2．We never waste too much water. （
3．There are all kinds of wild animals and plants on our Earth. （
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
