Time Zones时区
Our planet, the Earth, is the third planet from the sun.我们的行星，地球，是离太阳第三个行星。
It is a beautiful, rotating sphere.它是一个美丽的旋转球体。
The side facing the Sun is in daylight.面对太阳的一面是在日光下的。
The side facing away from the Sun is in darkness.背对太阳的一面处于黑暗中。
For example,whenit'sdaytimein the US, it's nighttime in China.例如，美国的白天，中国的夜晚
In fact, there's 12-hour time difference between Boston and Shanghai.事实上，波士顿和上海之间有12个小时的时差。
When it's midnight in Shanghai, it's noon in Boston.上海的午夜，波士顿的中午。
The Earth rotates from west to east.地球从西向东旋转。
To know which direction is east or west, watch the Sun.要知道东方和西方哪个方向，就看太阳。
The Sun travels through the sky from east to west.太阳从东到西穿过天空
The Sun comes upon the east and goes down in the west.太阳从东方升起，从西方落下。
Again, this is because the Earth rotates.这也是因为地球在自转。
It takes 24 hours for the Earth to make a complete rotation.地球需要24小时才能完全自转。
And that is the length of one day.这是一天的长度。
Because of the Earth's rotation, the Earth is divided into time zones.由于地球的自转，地球被划分为时区。
Some counties, such as the US, have several time zones.美国等一些县有好几个时区。
When it's 10 am in New York, it's 7 am in San Francisco.纽约是早上10点，旧金山是早上7点。
Europe and the US are separated by several time zones.欧洲和美国被几个时区隔开。
When it's 5:00 pm in Paris, it's 11:00 am in Boston.巴黎是下午5点，波士顿是上午11点。
So there's a six-hour difference between Paris and Boston.所以巴黎和波士顿之间有六个小时的时差
One large country, China, has just one time zone for the whole country.中国是一个大国，整个国家只有一个时区。
As a result, at the same time, some parts of the country can be dark and other parts can be light.因此，与此同时，这个国家的一些地方可能是黑暗的，而另一些地方可能是光明的。
As you travel around the Earth, the time changes.当你绕地球旅行时，时间会改变
The time of daydependsonyour location on the planet.一天的时间取决于你在地球上的位置。
When you travel east or west, you may cross several time zones.当你向东或向西旅行时，你可能跨越好几个时区。
For example, if you travel from Beijing to Los Angeles, you cross eight time zones.例如，如果你从北京到洛杉矶旅行，你会跨越八个时区。
That means when it's noon Sunday in China, it's 8:00 pm on Saturday in Los Angeles.这意味着在中国，周日中午的时候，洛杉矶是周六晚上8点。
For travelers, this means it can be very difficult to sleep after a long flight.对于旅行者来说，这意味着长途飞行后很难入睡。
The clock may say 8:00 pm, but for your body it's noon.时钟可能是晚上8点，但对你的身体来说是中午。
This is called jet lag.这就是所谓的时差反应。