老师的意思是你上课必须认真听讲。

The teacher meant that you must listen carefully in class.

youdao

在学校里，我必须认真听讲，并且在作业上丢掉粗心大意！

In school carefully to listen lecture, and no careless on the home work.

youdao

要想在这门课中取得好成绩，必须要认真听讲， 用心阅读指定书目。

Now, to do well in the course, you have to attend both the lectures and do the readings.

youdao

Now, to do well in the course, you have to attend both the lectures and do the readings.

要想在这门课中取得好成绩,必须要认真听讲,用心阅读指定书目

耶鲁公开课 - 心理学导论课程节选