Please watch your behavior.

 请注意自己的行为。

youdao

Watch your behavior, be calm, be polite, listen and follow the teacher, concentrate on the test, don't forget why you are here. Okay?

注意你的行为举止，平静、有礼貌、专心听、跟随老师的要求、注意力集中到考试上，别忘了你为什么来这儿，好吗？

youdao

Watch your behavior, be calm, be polite, listen and follow the teacher, concentrate on the test, don't forget why you are here. Okay?

注意你的行为举止，平静、有礼貌、专心听、跟随老师的要求、注意力集中到考试上，别忘了你为什么来这儿，好吗？

youdao