Mary is reading something about how to keep healthy on the Internet.
    （1）How often do you stay up late？
    （2）好的睡眠對(duì)你的健康很重要。You need about eight hours' sleep a night.Don't read or eat in bed.A cup of milk before sleeping may help you get a good sleep.Go to bed at the same time before midnight（午夜） and get up at the same time every morning.For more information，please visit www.Sleep.Com.
    How often do you exercise？If you want to stay healthy，try to（3）每天鍛煉30分鐘，每周三四次。For more information，please call Health Line at 180-2000.
    Studies show that the cold or flu virus（流感病毒） can live on our hands for long.So you should wash your hands often with soap and water.If you want to know more，please call Health Line at 180--1313.
    （4）Brush your teeth twice a day and see a dentist at least once a year. The oral examination（口腔檢查） is not only for the health of teeth，but also for the whole body.

（1）

你多久熬夜一次？

你多久熬夜一次？

（2）

Good sleep is very important for your health.

Good sleep is very important for your health.

（3）

exercise for 30 minutes every day，three or four times a week.

exercise for 30 minutes every day，three or four times a week.

（4）

每天刷牙兩次，每年至少看一次牙醫(yī)。

每天刷牙兩次，每年至少看一次牙醫(yī)。