请讲解一下这道题选D的原因.

A so直接跟形容词,应该是She is so beautiful 或者 so beautiful the city is.
B 如果用very也是直接跟形容词,即She is a very beautiful city.
C 如果用such,应该是such+名词,即She is such a beautiful city.
D quite可以和such一样用,即quite+名词,因此quite a beautiful city正确；quite也可看做very,即the city is quite beautiful,a quite beautiful city.
固定用法,需要记忆,多看就有语感了.