我刷完牙了用英文怎么说

"I have brushed my teeth" 是表达刷完牙的正确英文表达。

"Brush"是英语中刷牙的动词，来源于古英语"bryscan"，意思是"刷掉"。

例句:

I brushed my teeth before I went to bed. (我在睡觉前刷了牙。)
I always brush my teeth after I eat lunch. (我总是在吃完午饭后刷牙。)

"My teeth" 是指自己的牙齿，"have brushed" 是动词短语，表示已经完成的动作。