基于《懂你英语》：Leve 3 Unit 2 Part 4 Listening-Overview of Earth Level 3 Unit 3 Part 1 Listening-Life & Condition 2
embark on = 开始
interstellar journey = 星际旅行
今天的主题是：A Glimpse of Earth 地球简史
There are two things we are going to discuss in today's lession:
1.why the Earth is so specail.
如何地球如此特殊
2.what the Earth has been through.
地球都经历过什么
Part 1：Why the Earth is so special
为何地球如此特殊
depend on = 依赖，依靠
For example:
Plants depend on sunlight for energy.
atmosphere = 大气层；气氛；氛围
For example:
This restaurant uses music and lighting to create a romantic atmoshpere.
layer = 层
There was a layer of oil on the surface of the water.
The atmoshpere also protects us from the Sun's ultraviolet rays.
ozone layer = 臭氧层
The ozone layer absorbs most of the Sun's ultraviolet radiation.
臭氧层吸收了大部分来自太阳的紫外线辐射。
ultraviolet = 紫外线
四大洋：
the Pacific Ocean = 太平洋
the Atlantic Ocean = 大西洋
the Indian Ocean = 印度洋
the Arctic Ocean = 北冰洋
fossil fuel = 化石燃料
Natural resources,such as coal and oil,give us energy.
condition = 事物的状态
For example:
This house is in poor condition.
condition = 条件
However,for any form of life to exist,conditions must be right.
Part 2：What the Earth has been through. 地球都经历了什么
Altogether ,the Earth has gone through 5 mass extinction events.
Level 3 Unit 3 Card 1:
One extinction event happened about 250 million years ago.
这起物种灭绝事件就是二叠纪大灭绝。
die out = become extict = 灭绝
It took the Earth nearly 10 million years to recover.
地球在数百万年后才得以恢复。
白垩纪大灭绝
时间：
66 million years ago
结果：
the extinction of dinosaurs
During this extinction event,eighty percent of all life on earth die out,including dinosaurs.
白垩纪大灭绝导致了地球上80%的物种灭绝，包括恐龙在内。
global warming
现象
global temperatures are rising.
原因一：
Increasing amount of greenhouse gases.
greenhouse gases = 温室气体
carbon dioxide = 二氧化碳
the burning of fossil fuels = 燃烧的化石燃料
原因二：
cutting down of forests
Polar icecaps = glacier = 极地冰川
Pollution is now a growing proplem around the world.
Pollution posions the air and water that we depend on.
Two most harmful types of pollution:
1.air pollution
2.water pollution
Two major sources of air pollution
1.emissions from factories = 工业废气
2.exhaust from cars = 汽车尾气
smog = smoke + fog
PM = Particulate Matter = 颗粒物质
water pollution
原因一：
chemicals = 化学物质
原因二：
oil spills = 石油泄漏
Paris Aggreement on Climate Change = 《巴黎协定》
