beforehand

副词

1. 1

   事先、预先

   You should let the host know beforehand if you can't attend.

   如果你不能出席，应该事先告知主办人。

2. 2

   提早、提前

   We arrived half an hour beforehand to set up the chairs.

   我们提早半小时到，把椅子摆好。