题目

We can all have a bad night of sleep and that’s perfectly normal, but how could we try to improve both the quantity and the quality of our sleep?【1】Let’s start with regularity.【2】Regularity is king, and it will actually help your sleep, no matter whether it’s the weekday or the weekend or even if you’ve had a bad night of sleep. Many of us use an alarm to wake up but very few of us use a to-bed alarm, and that’s something that can be helpful.【3】It turns out that your brain and your body need to drop their temperature by about 1℃ in order to begin sleep and then to stay 如图所示，一个足球静止在水平地面上，请画出它受力的示意图。