如有可能留一副备用眼镜以防你常用的那副打碎或丢失。

If possible keep a spare pair of glasses accessible in case your main pair is broken or lost.

《柯林斯英汉双解大词典》

那一天他将会来访五次，以防你不在家。

He will come five times that day, in case you have gone out.

youdao

带着你的笔记以防你忘记了想要说什么。

Bring your notes with you in case you forget what you wanted to say.

youdao

But again, that we will supply for you on the exam just in case you forget it at that moment.

但在考试中我们会给出这个值,以防你当时忘记了。

麻省理工公开课 - 化学原理课程节选

So I'll bring a little bit of extra food. Just in case you run out.

我会多带一点吃的来。以防万一你这儿的东西不够吃。

Who 实战 - SpeakingMax英语口语达人