Tìm lỗi sai và sửa lỗi 1. The development in the field of robotics has been beneficial to the handicapped. 2. At the summer camp last year children swam, rode horses, and play baseball. 3. Tom has to go to the dentist's because of he has a bad toothache. 4. That's wonderful. I'm pleasing that you are working hard.  

1. has been beneficial => has been benefited

2. play => played

3. Because of => because

4. pleasing => pleased.