1. Moon over verb phrase, crush, to ...... because of dissatisfaction or infatuation stunned (stunned); Obsessively missing (loved ones); Obsessively missing, right...... Yearn for
You’ve been mooning over him for three months now.
You've had a crush on him for three months.
He spends most of his time mooning over Helen.
He spent his days obsessing with Helen.
2.moon about/around verb phrase, "to hang out, to spend time", especially to be listless and idle. (listlessly) loitering, (depressedly) passing time; It also has the meaning of "not doing business, idleness". Example:
Lettie was mooning around all morning, doing nothing.
Letty messed around all morning and didn't do anything.
He mooned around the street, hoping to see Anna.
He wandered the streets, hoping to meet Anna.
I wish you'd stop mooning about and do something useful! 我希望你别再闲混，去做点有用的事情！
3.once in a blue moon极少地；难得地；破天荒地; 千载难逢; 百年不遇
Once in a blue moon you get some problems.
Trouble is rare.
This is a once in a blue moon deal and only offered for a limited period!
This limited-time deal is a once-in-a-lifetime deal!
4.many moons ago 就等于 long time ago “很久以前”。
This word is mostly commonly found in literary works.
I weighed no more than him myself at that age, but that was many moons ago.
I myself couldn't have weighed him at that age, but that was a long time ago.
5.over the moon 是非常高兴; 乐翻了天; 狂喜; 欣喜若狂（extremely happy and excited），例句：
She's over the moon about her new job. 她对新工作非常满意。
She's over the moon about her new baby.
She gave birth to a little baby and was very happy.
— How does it feel to have won the championships?
— I’m over the moon!
— How does it feel to win the championship?
— I'm so happy!
6.ask/cry for the moon 或want the moon
Want to do things you can't do, want things you can't get, whimsical
Example phrase:
There's no point in crying for the moon.异想天开是没有用的。
I don’t ask for the moon; I just want him to listen to me for once.
I didn't ask too much, I just wanted him to listen to me carefully.
7. promise (sb) the moon
Make blank cheques;
He promised her the moon, but after ten years of marriage they hardly had enough to live on.
He made many empty promises to her, but after ten years of marriage, they could barely make ends meet.
Last: moon cake moon cake and the Mid-Autumn Festival moon landing, moonwalk, moon-face; Moonlight, Moonbeam