in case是连词，连接主句和从句。in case既可以引导条件状语从句；又可以引导目的状语从句；但是含义不同；表示条件含义是“如果，万一”；表示目的，含义是“以防，以免”。请看：

1. 引导条件状语从句

In case he comes, let me know.

如果他来的话，告诉我一声。

In case you should need any help, here's my number.

万一你需要帮助的话，这是我的电话号码。

In case we fail,we won't lose heart.

万一我们失败,我们决不会失去信心.

I have also sent you the book in case you need it.

我把书也寄给了你，万一你需要呢。

In case the house burns down, well get the insurance money.万一房屋烧毁了，大家会得到保险金。

2. 引导目的状语从句

Take a charger in case your phone battery dies.

带充电器以防手机没电。

Take a hat with you in case the sun is very hot.

带上帽子吧，以防太阳非常晒呢。

Our government should encourage more students to receive tertiary education in case the labor force is insufficient in the future.

我们的政府应当鼓励更多的学生接受大学教育，以防未来劳动力短缺。

Leave your key with a neighbour in case you lock yourself out one day.

给邻居留把钥匙，以防有朝一日把自己反锁在外面。

You hang around here in case he comes, and I'll go on ahead.

你在这附近等着以防万一他来了，我继续往前走。

I was going to get out of the building in case it went up

我怕大楼起火，正打算要跑出去。

She said nothing in case her temper slipped out of gear.

她什么都没说，免得按捺不住情绪。

It would be safer to take more money with you in case of emergency.

多带点钱保险些，以防急用。

Take some spare clothes in case you get wet.

多带几件衣服，以备身上弄湿了好穿。

He takes a torch in case it gets dark before he returns.

他带了手电筒，以备天黑以后回家之用。

I'll stay around in case you need me.

我就待在这儿，也许你用得着我。

He left the door ajar in case I needed him.

他虚掩房门，以防我会需要他。

In case anyone was following me, I made an elaborate detour

为了防止有人跟踪我，我特地绕了弯路。

She is afraid to contact the social services in case they are labelled a problem family.

她不敢联系社会服务部门，以免被当作问题家庭。

The authorities have urged people to stock up on fuel in case hostilities break out.

当局已敦促人们储存燃料，以防战事爆发。

He kept his voice low-pitched in case someone was listening.

他把声音放低以防被人听见。

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

如果有可能的话，最好准备一副备用眼镜，以防常用的那副眼镜打碎或者丢失。

最后，注意：

1). in case of

You'd better take an umbrella in case it rains. =

You'd better take an umbrella in case of rain.

你最好带把雨伞，以防下雨。

Our government should encourage more students to receive tertiary education in case the labor force is insufficient in the future. =

Our government should encourage more students to receive tertiary education in case of the shortage of labor force in the future.

我们的政府应当鼓励更多的学生接受大学教育，以防未来劳动力短缺。

2).in the case of至于..., 在...情况下

In the case of diligent students，attending university is not difficult。

对于勤奋的学生来说，读大学不是很难。

I dread to think what will happen in the case of a major emergency.

我不敢想在重大紧急情况下会发生什么。

Surgical training takes at least nine years, or 11 in the case of obstetrics.

外科至少需要9年的专业训练，产科甚至需要11年。