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Are you feeling tired in class every day? Are you feeling that you lose attention in class? Are you feeling “brain-dead” sometimes?
Well, if you answer “yes” to these questions, you are not sleeping enough. But you are not alone.
Use your time wisely
Sleep like a baby
Do you remember when you were a child and your parents asked you to take naps (小睡)?
Sleep more, suffer less
So how much sleep do you need? Researchers have done an experiment. They put people in an environment without clocks or windows and ask them to sleep any time they like.
| A．You should make plans of things you want to get done. |
| B．Some people feel tired the next day because of poor sleep. |
| C．Taking naps is important to you if you lose sleep during the night. |
| D．95 percent of people sleep between seven and eight hours out of every 24 hours. |
| E．Many people throughout the world haven’t got enough sleep, especially students. |
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
