I guess I could look up linguistic universals and find out what linguists think they might be. Maybe negation, words for spatial and temporal relations, words for things and qualities of things. Actions. Ways of ordering words. I'm thinking the beginning and ends of utterances are going to be important. That all languages will have units or phrases. They will have questions.
There are other ways of asking questions in Chinese. Putting a question word at the end like 'na li' (where?). Another one that means "what."
There are some verbal and temporal things: zai + verb for present progressive. Le after the verb to make it past.
It's not like you need some universal grammar at a deep knowledge. It's more that languages have things that they want to do, and then there have mechanisms for doing those things. So suppose negation is a thing you would expect a language to want to do. Then you would have some words that negate, or an affix, or whatever. Then a rule for where to place the negative element.