Mr. Smith, who often helped passers-by r
题型:选择题
问题:
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
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