1. happening or done quickly and without any warning.
All at once I felt dizzy and had to lie down.
2. at the same time.
I've had to deal with too many problems all at once.
英语词组固定搭配大全包含18674条英汉双解词组，基本涵盖了全部常用英文词组、短语的翻译及用法，是英语学习的有利工具。