This material represents a set of grammar problems that can be used either separately or together for revision classes. You might also like to work out your own way to work with them. The one that I use is quite simple, I assign the whole set as a hometask and ask to discuss all of the problems in small groups with the proceeding class discussion right at the next lesson. It the end, students write similar letters to me with questions that bother them most. I sometimes use these questions with other groups as well.