I am leaving for ShangHai on business.是什么意思?

I am leaving for ShangHai on business.是什么意思? 英语on的问题I am leaving for Shanghai on business.这里面为什么用on连接 I am ___(leave)for Shanghai.为什么是leaving? He does business in shanghai.he is leaving for shanghai the 改为间接引语.1.Mr.Wang said,"I will leave for shanghai on business mr wang said i willlever for shanghai on business next month Mr wang said "I'll leave for shanghai on business nest month mr.wang said ,“i will leave for shanghai on business next mo 直接英语变间接英语Mr.Wang said,"I will leave for Shanghai on business I am leaving for the supermarket. I’ll fly to Shanghai on business next Friday. I will go to Shanghai by plane on business