Ask是“问、要求”，out是“到(在)外面”。Ask somebody out字面意思就是“邀请某人出去”。这个短语用于什么场合呢？请看对话：

    A: I think your sister is cute. Is it fine with you if I ask her out?

    B: You mean you want to date her?

    A: Yes. I like her a lot.

    B: Aren’t you seeing Emily now?

    A: We broke up.

    Note: This expression means to “ask someone out on a date.” In heterosexual situations, it is usually the man who asks the girl out. When the man and woman have been on enough dates or get to know each other well enough, the guy will usually ask the girl to be his girlfriend. “Seeing someone” means to date someone. “Breaking up” means to part ways and end a relationship. “On the rebound” means one is in the sad period trying to recover from a breakup.