突发事件:
1. emergency
2. thunderbolt
用来指突发事件
Used to indicate a sudden occurrence.
这告示是千真万确的突发事件
The announcement was a veritable bolt.
这次突发事件定将导致一场危机。
This incident will surely bring on a crisis.
(站在悬崖的边缘上）；在一个扩展的意义上它指一件突发事变的可能性或临近（
stood on the brink of the cliff); in an extended sense it indicates the likelihood or imminence of a sudden change
