那位英语高手帮忙检查一下语法错误并改善一下，谢谢（学生好辛苦啦，可怜一下啊!)！

Shenzhen is an advanced city貌似不能说“高级”的城市吧，可以改为amazing，wonderful，modern等
it is very active and beautiful too. active建议改为dynamic（充满活力的）
We are trying our best to show our best .一个句子里最好不要有重复的单词，去掉第一个best吧
The project is nearly finish。finish建议改为finished
It is called ‘UU’ and painted as a big smile.建议改为It is called ‘UU’ and it‘s painted like a smiling face.
It is just like a big smile ang make others glad. glad建议改为happy
Come to Shenzhen and enjoy the warmth of it !感受温暖？建议去掉warmth吧，直接写enjoy the city

We are trying （hard）to show our best. 英语里面很少重复使用同一条短语的情况，尤其这是一个句子里面出现了2次。
The government has already decided就可以了，过去完成时一般都用于有过去的某个时间点作为基准，比那个时间点更靠前的时间或状态，一般用在时间状语从句里，不太会单独使用。
The project is nearly finished. 被动语态，也可以表示状态。

语法上大概就这些，再进一步的我也爱莫能助了，我汉译英很差劲的：）