20. I will appreciate it very much ________ you could change your plan a little bit to make it more workable.

A. if 　　　　　　　　　　　　　 B. that 　　　　　　　　 　　　 C. whether　　　　　　 　　　 D. unless

19. On the contrary, I think it is John, _________ you, _________ to blame.

A. more than; are 　　　 B. less than; who are 　　 C. rather than; that is 　 D. rather than; is