Half of the classdone most of the work. The restrather difficult.A. has, isB. have, areC.

Half of the class done most of the work. The rest rather difficult.
A. has, is
B. have, are
C. have, is
D. has, are

A. has, isB. have, are(答案→)C. have, isD. has, are解析：考察主谓一致.这里的class指的是学生们.一半学生也是复数,rest其余的,为抽象名词,不可数,用单数,故选C.

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