all at once

副词 all at once:

1. all at the same time
   同义词：all together
2. without warning
   同义词：all of a sudden

1. All at once, a rabbit came out of a hole.
   突然，一只兔子从一个洞中跑了出来。
2. All at once the door opened.
   门突然打开了。
3. All at once she lost her temper.
   她突然发起脾气来。
4. A wind arose, and rain drops began falling all at once.
   起风了，雨点忽然落下来。