Beijing,the capital city of China,is a very beautiful city.为什么要在Beijing。china后面加“，”这个句子的结构是什么，是什么句型？这是插入定语，用起来比较简单，比较复杂的是Beijing, which is the capital of China, is a very beautiful city.也可以说China's capital Beijing is a very beautiful city. 不过这个感觉上没有前面的好。