用ask for the moon表达“异想天开”

短语to ask for the moon直译是要天上的月亮，实际意思是说某人提出过分的要求，想要得不到的东西或是想做做不到的事儿。

• Bob‘s wife is always asking for the moon. He works hard 12 hours a day for poor pay, but she still expects expensive holidays and clothes.
• Don‘t ask for the moon, Mr Jones. Be reasonable, please.

值得注意的是，短语to promise the moon to someone的意思是向某人答应办不到的事儿，也就是汉语里常说的空口许愿。

• My husband promised me the moon when we got married: a big mansion, a flashy car and all the diamonds I could wear. But none of it happened!