I can hardly recognize you.

我几乎认不出你来了。

A: I can hardly recognize you.
甲:我几乎认不出你来了。
B: Yes, I made it.
乙：是的，这就是我想要的效果。
His face is virtually unrecognizable.
他的脸变得几乎让人认不出来了
I didn't recognize you with your mask on.
你带上面具我都认不出 了

May I have this dance, my lady?

我能邀您共舞吗，小姐？

A: May I have this dance, my lady?
甲：我能邀您共舞吗，小姐？
B: Of course. It's my honor.
乙：当然可以，这是我的荣幸。
You are such a graceful partner.
你真是个很优雅的舞伴
I've already promised someone.
我已经答应别人了。
I would partner John.
我是约翰的舞伴。