Mr. Smith, who often helped passers-by repair their bikes, said that what he did was not paid but __...
2022-11-18 23:26:39 47次 2015届湖北省高二下学期期中考试英语试卷（解析版） 单项填空 反馈错误 加入收藏 正确率 : 100%
题目内容：
Mr. Smith, who often helped passers-by repair their bikes, said that what he did was not paid but _______.
A. relevant B. optional C. suitable D. voluntary
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