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Once upon a time, a boy walked through the countryside. Suddenly he saw an angel in some clouds. The angel was singing a beautiful song.
“It must be the door to heaven, and that it will be fun to see what is up there”, the boy thought. He really wanted to go to heaven.
Just when he was going to give up, the angle appeared. The angel sang again and again.
It was dark. The boy sat down and had a rest. The next morning, when the sun appeared, it created a rainbow.
| A．But the angel disappeared soon. |
| B．The boy decided not to give up. |
| C．The boy listened to the song carefully. |
| D．So he started building a big tower of wood. |
| E．The rainbow led directly up to the door of heaven. |
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
