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Traffic lights are the same in every country. There are always three lights: red, yellow and green. Red means "stop" . Yellow means "wait" and green means "go" . In China, drivers drive on the right side of the road. In the US, drivers drive on the right side too. In England and Australia, however, drivers drive on the left side of the road. If you go by car, by bike or on foot, you must know the traffic rules.
1．There are always three lights in every country: red, yellow and green.2．Yellow lights mean "go".
3．In China, drivers drive on the right side of the road.
4．In the US, drivers drive on the left side of the road.
5．If you go on foot, you don’t have to know the traffic rules.
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
