◎ 题干

—— I can’t get through to the general manager’s office anyhow.
—— The line is busy. Someone _____ the telephone.
A.must useB.usesC.must have been usingD.must be using
◎ 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“—— I can’t get through to the general manager’s office anyhow.—— The line is busy. Someone _____ the telephone.A.must useB.usesC.must have been usingD.must …”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。