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Water is very important for us. We must drink water every day. We can’t live without water.
Water is everywhere around us. At home, we use water to wash clothes and dishes, cook rice and take a bath. At work, people use water to put out fires, to grow vegetables and make electricity.
But do you know there isn't enough water on the earth? We should save water and reuse water. Just do it, for the natural world.
1．People can’t live without water.2．We don’t need to drink water every day.
3．We can find water only in the sea.
4．Water has different kinds of uses.
5．There is enough water on the 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
