短文改错,请写出为什么错 .十个错误.

Yesterday,I go(改为went)shopping in the supermarket.As I was looking at the goods I noticed an old man who was (去掉was)seemed to be following me where(改为wherever) I went.As I moved,there he was,smiled(改为smiling) at me.I wondered if I had done something wrong.But I didn't think I had.So,I believed if(改为that) there must be something wrong with him.I became a bit scaring(改为scared).At the food section I was selecting the(去掉the) chicken when I felt a tap on the shoulders(改为shoulder).Turning around,I saw that it was(加上the) same man."Lady," he finally said,"you have your shopping basket."At that moment Irealized I miaunderstood him,so I said sorry for(改为to) him at once.