在 + 梦 + 中
The noun 梦 (mèng) means 'dream' and is used for both literal dreams during sleep and figurative dreams or aspirations. It appears in common expressions like 做梦 (to dream), 梦想 (dream/aspiration), and 在梦中 (in a dream).
我昨晚做了一个奇怪的梦。
Wǒ zuówǎn zuò le yī gè qíguài de mèng.
I had a strange dream last night.
他的梦想是当一名医生。
Tā de mèngxiǎng shì dāng yī míng yīshēng.
His dream is to become a doctor.
在梦中我回到了小时候住的地方。
Zài mèng zhōng wǒ huí dào le xiǎoshíhòu zhù de dìfāng.
In my dream I returned to the place where I lived as a child.