题型:阅读选择 题类:常考题 难易度:普通
福建省厦门市2018-2019学年八年级下学期英语期末质量检测试卷
Earth's atmosphere (大气) is made of the layers of air that is around Earth. Thanks to the O2 found in the atmosphere, humans and other animals can breathe.
The atmosphere has four layers. The closest layer to Earth is the troposphere. The troposphere reaches from Earth to about 8 to 15 kilometers above sea level (平面).
It includes most of the air and O2 in the atmosphere, so all life on Earth lives here. The closer to the ground, the warmer the air is. Higher up in the troposphere, the air becomes much colder.
The second layer of the atmosphere is the stratosphere. The stratosphere reaches to around 50 kilometers above Earth. Near the top of the stratosphere is the ozone layer (臭氧层). The ozone layer helps protect life on Earth from the sun's UV radiation. Unluckily, there are holes in several parts of the ozone layer. This could cause serious problems for life on Earth.
The third layer of the atmosphere is the mesosphere. It reaches up to around 80 kilometers above Earth. The mesosphere has the coldest temperature in the atmosphere. It can be as cold as -100℃ there.
The fourth layer is called the thermosphere. It reaches up to around 600 kilometers above Earth. This is where outer space begins. The international space station runs around the planet from this layer. The temperature here is very high. It gets up to 1, 200℃.
试题篮