They are studying for a test – they are preparing to take an examination.

他们正在为考试而学习——他们正在准备参加考试。

So, if you're a history teacher, you have to take an examination on history.

所以，如果你是历史老师，你就必须参加历史考试。

In many places, you have to take an examination, a test, to see if you have the knowledge in order to get a certain government job.

在很多地方， 你必须参加考试、测试，看看你是否具备知识才能获得某个政府职位。