你最好拉紧主帆索。
If such an earthquake happened today, it would be felt from the Rocky Mountains to the Atlantic Ocean and would flatten most of the cities in the Mississippi valley.如果今天发生这样的地震，从落基山脉到大西洋都会有震感，而且会把密西西比河谷的大部分城市夷为平地。
If a 100-foot-wide asteroid hit Earth, the shock wave from its explosion in the atmosphere could flatten trees and kill every large animal for hundreds of square miles.如果一个100英尺直径的小行星撞击地球，它在大气中爆炸产生的冲击波可以令数百平方英里内所有的树木倒伏，并杀死所有的大型动物。
