问题补充：
--- What do you think of the math problem ?
--- It’s very hard and nobody has .
A. put it out
B. helped it out
C. worked it out
D. solve
答案：
A. put it out
B. helped it out
(答案→)C. worked it out
D. solve
解析：句意：——这道数学题你认为怎么样？——我认为非常难，没有人能算出它。worked out算出，put out生产、伸出，help out帮助，solve解决（问题）
