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Thirty years ago, Sun Yang was eight. He lived in a small village. There were no tall buildings in his village. There were no cars, either. But there were many trees and flowers. And there was an old school. Sun Yang went to school on foot. Now the village is different. There are tall buildings everywhere. The trees become taller and taller. There is a new school. It’s big and nice. Sun Yang loves the village very much.
1．Sun Yang is forty years old now.2．There were no tall buildings in Sun Yang’s village thirty years ago.
3．You couldn’t see any flowers in Sun Yang’s village thirty years ago.
4．Thirty years ago, Sun Yang went to school on foot.
5．The trees in Sun Yang’s village become taller and taller.
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
