求老师看看下面这些句子有没有问题

第一句话不用过去时更好,因为是描述地理位置,直接用一般现在时.XX is a beautiful city which situates（或者用 is located ） in the south of China.
第二句话有语病,定语从句使用不当,这样子更改：.It has a population
of 12 million and most of them come from the inland.
第三句话也有语病,且为了更显地道,调整一下时间状语的位置,更改为：There are a number of visitors from all over the world who would like to pay a visit to XX every year.
第四句话也有语病,更改为：As is known to all,people who live there are hardworking.
第五句话改为：They make great contributions to the development of XX and really play an important role in it.
再问： 那第2、5句怎么改成定语从句呢
再答： It has a population of 12 million, most of whom come from the inland. They make great contributions to the development of XX , which enables the children to enjoy beautiful life there.