上课时你必须认真地听老师讲。

You must listen to your teacher carefully in class.

youdao

课堂上不要听音乐或玩游戏，上课时我们必须认真听老师讲课。

Don't listen to music and play games in class. We must listen to the teacher carefully in class.

youdao

课堂上不要听音乐或玩游戏，上课时我们必须认真听老师讲课。

Don't listen to music and play games in class. We must listen to the teacher carefully in class.

youdao