---Look at these tracks. It be a wolf.”
---Don’t be so sure. I think it be a fox.
A. must; could
B. may; might
C. need; must
D. could; need
网友回答
(答案→)A. must; could
B. may; might
C. need; must
D. could; need
解析：考查情态动词。Must可表示肯定推测，意为“一定”；could“可能”，表示的可能性没有can大，但比may大。句意“看那些脚印。它一定是一匹狼。”“不要那么肯定。我认为是一只狐狸。”故选A。