他需要持续的监督。

He needs constant ___supervision.

除非有老师的监督，否则学生不得接触这些化学品。

Students are not allowed to handle these chemicals unless they are under the ___supervision of a teacher.

您可以将您的孩子交由训练有素的工作人员照看。

You can leave your children under the ___supervision of well-trained staff.