◎ 题干
Nobody knows how people first came to these islands. They _____ from South America on rafts.
A .must have sailed 
B. can sail 
C. might have sailed
D. should have sailed
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◎ 解析
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◎ 知识点
    根据n多题专家分析,试题“Nobody knows how people first came to these islands. They _____ from South America on rafts.A .must have sailedB. can sailC. might have sailedD. should hav…”主要考查了你对  【虚拟语气】【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。