He walked back and forth in the room, thinking about the problem.他在屋里来回走动，思考着问题。

Don't say this back and forth, I know how to do.不要反复说这个，我知道该怎么做。

Alease don't go back and forth, I'm doing my homework.请不要来回走动，我在写作业。B:Oh, I'm sorry, I didn't notice that you were doing your homework.哦，对不起，我没注意到你在写作业。