正确答案为：
He failed the exam,__didn't__ ___he_?
He made few mistakes in the exam,__did__ __he__?
两者的区别就是第一句前面为肯定,fail是失败,它表示肯定,所以后面用否定.
第二句有few,为否定,所以后面用肯定.
^___^
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