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Tom has some good friends. The river is their home. In hot days, they come out from the river, they like playing in the sky. They can fly higher and higher (越飞越高). They are colder and colder (越来越冷). Then they get together and become black clouds. When they become cold enough (足够冷). They want to go home. At last, they fall down into the river. What are Tom and his friends? They are water drops (水滴).
1．Tom’s friends live in a river.2．In cold days, they like playing in the sky.
3．They can fly higher and higher.
4．They get together and become wind.
5．Tom and his friends are water drops.
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
