What a beautiful city it is！
（这是个）多么美丽的城市啊！
句型：
（1）what + a/an +形容词+单数可数名词+陈述句（主语+谓语）
What a beautiful city it is!
What an interesting story she told!
（2）what+形容词+复数可数名词/不可数名词+陈述句（主语+谓语）
What expensive watches they are!
What terrible weather it is!