75%前面为什么要加with?And with 75% of the world's population predicted to live in cities by 2050,the transport system and emergency services will need to modernise to cope with all the new arrivals.

75%前面为什么要加with?And with 75% of the world's population predicted to live in cities by 2050,the transport system and emergency services will need to modernise to cope with all the new arrivals. 英语中 ,and 中 and本身就是连词为什么前面要加逗号那 run with the foodball 为什么球类前面加the china and the USA为什么USA前面要加定冠词THE it is a volvo为什么volvo前面要加a,a 还有and this is naoko she is japanese 前面要and干吗 电话号码前面为什么要加8? 为什么名词前面要加the natural disaster前面为什么要加the 为什么 wolf前面要加the UK前面为什么要加the? 部分英语前面为什么要加the? erhu为什么前面要加the 为什么right前面要加the you前面为什么要加are 为什么北京前面不要加the,为什么太阳sun前面要加the? our teaching building is surrounded with trees and flowers为什么trees 和flowers的前面不用加the呢?我现在的问题是不知道什么时候要加the什么时候要加the.我很难理解专业的解答（虽然这个问题很简单,但对 I usually have chicken with vegetables and some rice为什么 vegetable 要加s and前面加逗号还是or前面加逗号啊?