去年一月3日，20小时的平均降雪量为11毫米。

On 3 January last year, the average snowfall in 20 hours can reach 11 millimeters.

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研究发现，在年龄低于40岁的研究对象中，晚间平均睡眠时间不超过5小时的腹部脂肪增加量高于6至7小时平均睡眠的研究对象。

Among participants younger than 40, the study found, those who said they slept for five hours or less each night gained more belly fat than those who averaged six or seven hours of sleep.

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首先，确定自己每24小时期间个人平均所需睡眠量，维持一个稳定的警觉水平。

First, establish your average personal sleep requirement in each 24-hour period to maintain a consistent level of alertness.

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And when we're talking about the amplitude of the wave, we're talking about the deviation from that average level. So, if we define the average level as zero, you can have either a positive amplitude or a negative amplitude.

当我们讨论一个波的振幅时,我们说的是偏离平均位置的量,如果我们把平均位置,定义为零的话，那幅值不是,正的就是负的，有时候人们在。

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