我也给他买了一份人寿保险以防万一。

I have also taken out a life insurance policy on him just in case.

《柯林斯英汉双解大词典》

你很可能无需打电话，不过还是记下我的电话号码吧，以防万一。

You probably won't need to call—but take my number, just in case.

《牛津词典》

可能下雨，拿把伞吧，以防万一。

It may rain; you'd better take an umbrella just in case.

《新英汉大辞典》

We handed out again the game with the numbers, but just in case, let me just read out the game you played.

再来介绍一下这个数字游戏,但是以防万一,我来介绍下游戏规则

耶鲁公开课 - 博弈论课程节选

We got an easy one. Let's just for the heck of it I should have found some better examples before I tried this. No mutant spiders here.

我们有了个简单的数字,让我们以防万一,我应该在尝试这个之前找几个更好的例子。

麻省理工公开课 - 计算机科学及编程导论课程节选

I think there probably is one in there somewhere, but just in case, we have had two in class, there's one on the handout.

我记得讲义里好像讲了,以防万一,我们课堂上有两个定义,在其中一个讲义里面

耶鲁公开课 - 博弈论课程节选