promise the moon -用法

promise the moon

promise sth．impossible承诺不可能的事

I can't promise you the moon，but I'll do the best job I can．我不能乱下承诺，不过我会尽力而为。

Nobody paid any attention to him because he always went around promising everyone the moon．他总是到处开空头支票，所以没人理睬他。