--The boys are not doing a good job at all are they?-- . A. I guess not so B. I do

问题补充：

----- The boys are not doing a good job at all, are they? ---- .

A. I guess not so

B. I don’t guess

C. I don’t guess so

D. I guess not

答案：

A. I guess not so

B. I don’t guess

C. I don’t guess so

(答案→)D. I guess not

解析：I guess not. 我认为他们没做好工作。为了避免重复，用not替代are not doing a good job at all。