GbEng
我要上厕所. I need to go to the bathroom.
厕所现在无人使用. The lavatory is vacant.
我可以用用你们的厕所吗--我实在憋不住了. May I use your lavatory I'm bursting! ie I need to urinate urgently.
我憋不住了(要小便), 得找个厕所. I can't hold out (ie retain my urine) much longer; I must find a toilet.