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This is our earth. The green part is land. The blue part is sea. The white part is clouds. Our earth is very beautiful. About 71% of our earth is covered by water. But only about 0.77% of the water can drink. Many years ago, the earth was very clean. But nowadays, there is much pollution on the earth. People are polluting the land, the water and the air. People must stop doing that. We must protect the earth.
1．What colour is our earth? ( )| A．Green, blue and red. | B．Blue, white and grey. | C．Green, blue and white. |
| A．71% | B．29% | C．6.1% |
| A．About 71% of our earth is covered by water. |
| B．The white part on the earth is water. |
| C．The earth was very clean many years ago. |
| A．pollution | B．water | C．land |
| A．The river, the lake and the cloud. | B．The trees, the air and the land. | C．The land, the water and the air. |
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
