皮毛(pímáo) skin and hair; superficial knowledge

Usage：

“皮毛”本来是指禽兽的皮和毛的总称，多比喻学识方面表面的、肤浅的东西。
“皮毛” was originally a general term for animal skin and hair. It more often is a metaphor for something shallow or superficial in knowledge.
Sentences:

1、Duìyú zhège lǐlùn ，wǒ zhǐ dǒngdé yīdiǎnr pímáo.
对于这个理论，我只懂得一点儿皮毛。
Regarding this theory, I only know some superficial knowledge.

2、Nǐ gāng xuéle diǎnr pímáo, jiù yǐwéi zìjǐ quán dōu dǒngle.
你刚学了点儿皮毛，就以为自己全都懂了。
You studied but some superficial knowledge and already think you understand everything.