Tìm va sửa lỗi trong các câu sau: I don't know what is he doing at the moment

tìm va sửa lỗi trong các câu sau
1. I don't know what is he doing at the moment
2. let's stop to work for a while.i'm getting tired
3. jane hasn't  work for lát summer when the factory closed down
4. the big present ís wrapped in red papers is five dollars
5.he has learn chinese enough to live in china
6. mr.nam used to travel a lot but now he didn't