There is no doubt Tom is a good clever boy.A. whetherB. ifC. whenD. that

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A. whether
B. if
C. when
(答案→)D. that
解析：考查doubt固定用法。当到doubt前为肯定形式时，后接if或者whether从句；当doubt前为否定形式时，后接that从句。No表达否定含义，故选D。