Keep an Eye on.

密切注视

It means to watch or to take care of something.

该短语意思是注视或者照顾某事某物

Paul kept an eye on his younger brother in the mall.

保罗在商场看着他的弟弟

Will you keep an eye on my bag while I buy something?

我去买东西的时候你能帮我看一下包吗

The teacher kept an eye on her students during the test.

考试中，老师监视着他的学生