The body and health

看病 (kàn bìng) is to see a doctor. Literally it is to look at illness, and both the patient and the doctor can be the subject: the patient goes to have the illness looked at, the doctor looks at it.

This verb-plus-object habit is everywhere in Mandarin and it is worth naming early, because it explains a lot of vocabulary that otherwise has to be memorised whole.

睡觉 (shuì jiào) is to sleep, literally to sleep a sleep. 吃饭 is to eat rice. 说话 is to speak speech. The object is not optional decoration; it is part of the verb, and dropping it usually leaves something that sounds incomplete.

心 again

心 (xīn) is the heart as an organ and the mind as a faculty, which you met with the feelings. Here it is doing its literal job, and it is worth holding both senses at once rather than picking one.

头发 is head hair

头 (tóu) is the head. 头发 (tóu fà) is the hair on it, and the reading of the second character shifts in speech to a neutral tone.

The distinction matters because Mandarin does not use one word for hair anywhere on the body. 头发 is specifically the hair on your head, and that specificity is typical.

眼睛 (yǎn jīng) is the eye, and it is nearly always two characters. The single 眼 appears inside compounds but rarely stands alone in speech.

Two words for hurting

痛苦 (tòng kǔ) is suffering, in a broad and often emotional sense. It is not what you say about a sore knee.

For physical pain the everyday word is 疼 (téng) or 痛 (tòng) on its own: 头疼 is a headache, literally head-hurt. The structure is body part plus the hurting word, and it is refreshingly simple after Spanish and French.

病 does everything

病 (bìng) is illness as a noun, and to be ill as a verb. 我病了 is I have fallen ill. 医生 (yī shēng) is a doctor and 医院 (yī yuàn) is a hospital, both built on 医, the character for medicine.