To work in pairs is to work in a group of two people. 两个人一组就是两个人组成一组工作。

We did this project in pairs. 我们两人一组做了这个课题。

He'll do this project alone. 他会一个人做这个课题。

Tom, are you studying alone？Do you need help? Tom,你一个人学习吗？你需要帮助吗?

We did this project in groups of five. 我们是五人一组做的这个课题。

You can study in groups, but you must take the test alone. 你们可以分组学习，但是你们必须一个人参加测试。

This school has a big cafeteria, You can eat breakfast and lunch here. 这个学校有一个大食堂，你可以在这吃早饭和午饭。

Let's meet in cafeteria before lunch. 我们午饭前在食堂见面。

If something is taken, It's not available.占据。

Is this seat taken，这个座位有人吗（这个座位有人了吗-错误）

To take a seat is to sit down in an available chair or couch.(couch，沙发，take a seat-入座）

You can take a seat over there, next to the window. 你可以坐在那里，在窗户旁边。

Could you take the seat at the front, That seat is taken.那个座位有人了。