I feel that FTs should not teach writing in China, but twice I was asked to do so.

The fact that the vast majority of students don't understand what the FT is saying about grammar, format and style is probably a good thing.

I found knowing some grammatical vocabulary in Chinese to be valuable, but my knowledge of written Chinese grammar is nil, so I was unable to do contrastive instruction, which is how written language is best learned by second language learners.

As you suggest, my use of 'single quotation marks' is a style faux pas.