I. words and expressions
1. Be in danger 处于危险之中
This book says that our world is in danger. 这本书说我们的世界处于危险之中。
2. vital very important and essential adj. 重要的
it is vital that we do something to save the earth. 我们得做些什么来拯救地球是至关重要的。
3. the threats to 对于……的威胁 threaten v. 威胁
First of all, what are the threats to our environment? 首先，对于我们环境的威胁是什么?
4. Keep sth from doing 阻止……做某事
The atmosphere is acting like the glass letting sunlight in while keeping much of the warmth from getting out.
大气层像个玻璃罩，吸入阳光而阻止热量散失。
