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Bicycle riding is good exercise. It helps people become f1．. Bicycle riding can make the riders’ hearts and lungs strong. It is also good for the environment because bicycles do not cause 2． (污染).
Bicycles share the road with cars and trucks. Drivers do not always notice bicycles. So bicycle riders must p3． attention to the traffic around them and know traffic signals. They must know and obey the safety r4． . They must wear helmets to protect their heads. If they ride at night, they should have lights on the bicycle or wear light-colored clothes. In case of an accident, bicycle riders should know how to give first aid. If an injury is serious, they must call 120 for help. In a word, the best way to be safe is to be 5． (小心的).
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
