Answer:  Let us understand the situation which frequently prompts this question. Your grades are something less than you would like. This reflects that you are having difficulty with the work already assigned, or haven't done it sufficiently to perform well on exams. You are now asking for still more work to do to get "extra credit" when you haven't gotten the basic credit already provided.

Further implied in the question is that you want me to give you some perfunctory task so that you can get credit that others do not get and thereby better your class standing to the detriment of others. This would be unfair to the others.

I cannot in good conscience make a special arrangement with you to the exclusion of others. I try to incorporate as many credit bearing exercises as possible to give every student ample opportunity of demonstrating to me that the course goals have been met, and that all the material of this course has been learned. To do otherwise would be unfair to other students.