Modern Chinese:
There are many versions, such as Huang Liao version, Hu Yushu version, Zhang Bin version, Shao Jingmin version and so on. , but the difference will not be particularly great. If you are preparing for the postgraduate entrance examination, it is recommended to have a targeted look. What version is required by the school that wants to take the exam, mainly depends on which version.
Ancient Chinese:
Of course, Wang Li's ancient prose is the most classic.
And Guo Xiliang and others.
Linguistics:
Xu Tongqiang's outline of linguistics is certainly a must-see.
There are also some influential ones, such as "800 words of modern Chinese", "Grammar Lecture Notes" by Zhu and "Practical Modern Chinese Grammar" by Liu Yuehua.
Teaching Chinese as a foreign language:
Liu Shun's Introduction to Teaching Chinese as a Foreign Language
Zhao Jinming's Introduction to Teaching Chinese as a Foreign Language, etc.
I suggest you go to this website, the bibliography has been sorted out:
/doulist/ 10 1585/？ Start =25
For reference only. Good wishes!