I don’t doubt she can do it well but I doubt she is willing to do it.A. that; ifB. that

问题补充：

I don’t doubt she can do it well, but I doubt she is willing to do it.

A. that; if

B. that; that

C. if; if

D. if; that

答案：

(答案→)A. that; if

B. that; that

C. if; if

D. if; that

解析：句意：我不怀疑她能做好这件事，但是我怀疑她是否愿意做这件事。Doubt前有否定词时后面用that引导，而前面没有否定词时，要用whether或if或特殊疑问词来引导，表达疑问；故选A。