often do some work at weekends .A. Voluntary …volunteersB. Volunteers …voluntaryC. Volunte

网友回答

A. Voluntary …volunteers
(答案→)B. Volunteers …voluntary
C. Volunteers …volunteered
D. Volunteers … volunteering
解析：句意：志愿者经常在周末做一些自愿的工作。Volunteer志愿者，voluntary形容词自愿的。故选B。