一战700，二战640，恳求建议

I would not care very much to retake unless you verbal is too low. This is an unqualified opinion passing from some of my friends, that is because there are two many model essays and sometimes applicants hire professionals to write for them, a high score in the AWA can show consistency and genuiness on for your answers to those questions and essays required. Depend on the schools that you apply, you may take some other english test as a substitute as you are from China.

And there is no limit for you to retake, the universe of the AWA is less than 400 possibilities.

Good Luck.