短文改错 （共10小题，每小题1分，满分10分）
下文中共有10出语言错误。请在有错误的地方增加、删除或修改某个单词。
注意：1. 每句不超过两个错误；
2. 每处错误及其修改均仅限一词；
3. 只允许修改10处，多者（从第11处起）不计分。
I have happy family. My father and mother are old workers. They work on a big factory. They work very hard. They make a lot different machines for the farmers. These machines can help the farmer to do lots of farm work. I have a brother and a sister . My brother lives in Beijing .He studies in a middle school there. He teaches English. My sister and I are all students. But we are in the different grades ,she’s in Grade 3 and I’m in Grade 2. I’m very good at English. My sister often help me with it. They study hard for the people.