Definition
To be out of touch with reality and immersed in daydreams or fantasies.
脱离现实
She's always distracted, it's like she has her head in the clouds.
她总是心不在焉，好像她的脑袋在云端里。
He's always daydreaming; his head must be in the clouds.
他总是做白日梦；他的脑袋一定在云端里。
You can't always have your head in the clouds; you need to face reality.
你不能总是脑袋在云端里；你需要面对现实。