什么情况下加ing

介词后面动词要加ing (比如 be good at doing)进行时动词要加ing （比如现在进行时：be doing）固定短语搭配 （比如：enjoy doing sth)动词在句首作主语的时候要加ing,祈使句除外 （比如：Reading books is good for...Five one cheerleading continues from the photographed Dongdong Oh翻译- - 发现每次你给我翻译的东西都是看不懂的我很想知道是哪里来的句子打错了是Five one people in the supermarket shopping- -差别好大滴中国式英语吧这句：Five one people in the supermarket shopping （五一人们在超市购物？）哈哈,不能这样表达People go shopping in the supermarket on May 1st.五一人们在超市购物跟这个英语意思老师说一样我翻译出来是史密斯先生在国王街偷盗翻译感觉有点尴尬