1. I am the one-woman kinda man.

　　我是那种从一而终的男人.

　　2. He is dating another girl behind her back.

　　他脚踏两条船.

　　3. Are you hitting on me?

　　你现在是在跟我搭讪吗?

　　4. I have a crush on you.

　　我对你非常着迷。