" To keep an eye on" someone is to watch someone, especially to make sure that person doesn't do anything wrong, or if we're talking about a young child, to make sure the child doesn't hurt himself.

“To keep an eye on” someone 是指监视某人，特别是要确保那个人没有做错任何事， 或者如果我们谈论的是年幼的孩子，要确保孩子不会伤害自己。