beforehand
单词辨析：
指在时间上先于另一事发生或完成，尤用于谈论准备或计划的事情。
If you have completed most of the homework beforehand, you'll enjoy the evening more.
如果你预先把大部分家庭作业做完了，这个晚上你会玩得更开心。
Please inform us of your arrival time beforehand.
请事先通知我们你抵达的时间。
Saunas can be dangerous if misused. Avoid a big meal beforehand.
洗桑拿浴如果方法不当会有危险，浴前切忌饱食。
How could you tell beforehand that I was going to buy a Ford?
你怎么会事先知道我要买一辆福特轿车？
词义同 beforehand，常可换用；但以 ahead of time/schedule 出现时，则其中的 ahead 不可与 beforehand 换用。
Do book ahead/beforehand as the hotel is very popular.
该酒店非常受欢迎，请务必提前预订。
Winter weddings need to be arranged months ahead/beforehand.
在冬季举行婚礼需要提前几个月作安排。
If you had warned me ahead of time, I wouldn't have done that.
如果你预先警告我，我就不会那样做了。
The train left 3 minutes ahead of schedule.
火车提前3分钟离站了。
相关例句：
And if you know beforehand will you not be sad?
如果你提前知道了，你就不会难过了吧？
Claire wished she'd primed Sarah beforehand
克莱尔真希望她事先指点过萨拉。
Beforehand, some were asked to write about an experience that had angered them.
事前，有的被要求写了一个经验，激怒了他们。
It had been arranged beforehand.
一切都事先料理好了。
Make a list of your questions beforehand.
事先列出你的问题。
Saunas can be hazardous if misused. Avoid a big meal beforehand.
洗桑拿浴如果方法不当会有危险，浴前切忌饱食。