◎ 题干
Even the top students in our class can't work out this problem. So it _____ be very difficult.  
[     ]
A. need
B. may
C. can
D. must
◎ 答案
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◎ 解析
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◎ 知识点
    根据n多题专家分析,试题“Even the top students in our class can't work out this problem. So it _____ be very difficult. [ ]A. needB. mayC. canD. must…”主要考查了你对  【情态动词】  等知识点的理解和应用能力。关于这些知识点的“档案”,你可以点击相应的链接进行查看和学习。