going shopping,为什么shopping还要加ing?

going shopping,为什么shopping还要加ing? she was going out shopping.为什么还要加out I love shopping.那个Shopping为什么要加-Ing He is going shopping为什么前后都要加ing shopping center shop后面为什么要加ing? 为什么often go shopping with sb.中shop要加ing形式 she likes going shopping 为什么shop也要变 为什么是many people going shopping Are you going shopping with me tonight中为什么going和shopping都用in We going to shopping what about going shopping shopping