Donald Trump reportedly only sleeps for four hours a night, while some of us wake after seven hours wishing we could have a couple more. But how much sleep do we really need, and what time should we go to bed?

据报道，美国总统Donald Trump每晚只睡4个小时，而我们有些人睡了7个小时后才醒来，还希望能再多睡一会儿。但是我们到底需要睡多久，什么时候该睡觉呢？

reportedly：据说

wake：醒来

According to the Daily Mail, there will be days when you can't get to bed early or you don't have time for a lie-in, but there is a way to time your slumber to maximise the chances of waking up feeling refreshed and ready to face the day.

据“每日邮报”报道，有一些日子你不能早睡或者是没有赖床的时间，但是有一种方法能让你的睡眠时间尽可能延长，醒来时充满能量地面对新的一天。

slumber：睡眠

maximise：最大化

A new online sleep calculator can work out what time you need to go to bed just by knowing when you need to be up. It calculates the time using information on the body's natural sleep pattern, which works in 90 minute cycles.

一个新的在线睡眠计算器通过你起床的时间就可以计算出你什么时候该睡觉，这款计算器利用90分钟为循环的身体自然睡眠模式来计算出时间。

calculates：计算

pattern：模式

Being woken by an alarm in the middle of one of the 90-minute cycles, and potentially interrupting deep sleep, is often what makes people feel groggy and unwilling to get out of bed.

在90分钟的睡眠周期内被闹钟叫醒，有可能中断深度睡眠，总会让人感觉到昏昏欲睡并不愿意起床。

interrupting：中断

groggy：昏昏沉沉

For example, if you need to wake up at 7am, simply put that into the easy-to-use website and it suggests that you go to bed at 9.46pm, 11.16pm, 12.46am or 2.16am for the best night's sleep.

例如，你需要早上7点起床，只需要把起床时间输入到网站中，它就会建议你9.46pm，11.16pm，2.46am 或2.16am睡觉，从而得到最好的睡眠。

easy-to-use：容易使用的

suggests：建议

Adults need seven to nine hours per day, while 7 to 12 year-olds need 10 to 11 hours. If the whole family needs to be up at 7am you could send the children to bed at 9.46pm and stay up a little later yourself until 11.16pm.

成年人每天需要睡7至9个小时，7到12岁的儿童需要10到11个小时的睡眠。如果整个家庭都需要在早上7点起床，那么就在9.46pm让孩子们睡觉，自己可以晚一点在11.16pm睡觉。

adults：成年人

stay up：不睡

If you have trouble getting to sleep the Sleep Council recommends making sure your bedroom is completely dark, tidy and not too hot or cold, as well as avoiding using phones, laptops or TVs in the bedroom.

如果你的睡眠质量不好，睡眠委员会建议保持卧室完全黑暗，整洁，不太热也不太冷，避免在卧室内使用手机、笔记本电脑或电视。

recommends：建议

avoiding：避免