Then rinse under running water. In a public restroom, if you dry your hands with a paper towel, you should also use the towel to shut off the water and open the door.

VOA: special.2010.09.29

You want to ask to use the restroom as politely and as softly as you can.

你想要尽可能礼貌委婉地请求使用洗手间。

I wonder if 课堂 - SpeakingMax英语口语达人

I wonder if I could use the restroom.

我想知道我可不可以用这个洗手间。

I wonder if 课堂 - SpeakingMax英语口语达人

and you really need to use the restroom.

你得去下洗手间。

I wonder if 课堂 - SpeakingMax英语口语达人