---I find the more we study, the more difficulty we have out Maths problems.
---Oh, I agree with you. Maths is more and more difficult.
A. worked
B. work
C. works
D. working
网友回答
A. worked
B. work
C. works
(答案→)D. working
解析：考察非谓语动词。句意：解决这个数学问题，我发现我们越研究,我们的困难越多。选D，现在分词作状语表示正在发生的伴随性的动作，其逻辑主语为句子的主语。