head in the clouds字面意思脑袋在云里，看到的全是迷迷蒙蒙的幻想世界。形容人心不在焉总在做白日梦，活在自己的幻想中。

【例句】
I was really embarrassed& the teacher asked me a question and I didn''t even hear him; I was daydreaming and my head was in the clouds.
老师问我问题，我根本没有听见。那时，我刚好在做白日梦，思想在开小差。

A good artist should have his head in the clouds sometimes, but his feet always on the ground.
一位好的艺术家有时应富于幻想，但始终要脚踏实地。