我们现在正在上课，请保持安静。

We are in class now, please be quiet.

她正在上课，不能接电话。

She is in class and cannot take the call.

他们每天早上八点正在上课。

They are in class every morning at eight.

我们的老师正在上课时很严格。

Our teacher is very strict when we are in class.

当你正在上课时，请不要玩手机。

Please do not play with your phone while you are in class.

校长进来时，我们正在上课。

We were having our class when the headmaster came in.

有一张展示的是在一个农村的教室里，一些学生正在上课，在教室的泥地面上还有一些泥水坑。

One showed students at their desks in a rural classroom, surrounded by muddy puddles on a dirt floor.