normally both “做” and “作” can be used to express the meaning of DO, but usually we use “做” to mean do something that specific, for example“做饭”. And “作” to express doing sth which is abstract and using in written language, especially for some fixed words like “作对”. and your question about “工作” is a fixed word and the meaning work is not specific( didn't tell you what to do during working)

Hi Quin: 做(v.).: It is similar to 'do' in English. Therefore, it is usually placed before a noun or a noun phrase. Apply: 做(v.)+(a noun or a noun phrase)= Verb phrase. Noted that following noun or noun phrase has to make sense. For example: 做菜=To cook，做事=To do something，做愛=To make love, 做家事= To do house chores 作(noun): In Mandarin, we can place two nouns together to make a noun phrase. Apply: 作(noun)+(noun) = Noun phrase. Noted that they have to make sense as well. For example: 作業=(homework), 作家=(writer) Annotation: 工作(n.)= Job or a piece of work 工作(v.)= To work 創作(n.)= A piece of creation 創作(v.)= To create 做作業= To do one's homework hope it helps

Maybe one more thing to add: while the two characters sound the same in Mandarin, they historically had different pronunciations, and still do until today in the South： Cantonese： 作 zok3 做 zou6 Hokkien: 作 tsoh4 / tsok4 做 tsò / tsuè So, basically they are two different words, one ending in a -k and the other in a vowel. In Mandarin, all final consonants but for -n and -ng were lost, so the two became homonyms, a bit like ear (German: Ohr) and ear (of corn, German Ähre) in English ...

做=do (verb) 工作=work (noun) we can say 你是做什么工作的?=what do you do? we usually say 工作，作业，作文，作品..//做饭，做梦，做事... 做and作 are same pronunciation, but different meaning.