on cloud nine
飘飘然如上九重天
He was on cloud nine after winning the marathon.
他赢了马拉松比赛之后，极度兴奋。
head in the cloud
不切实际，好高骛远
You can't always have your head in the cloud, you need to be down-to-earth.
你不能总是那么好高骛远，要脚踏实地一些。
