I wonder whether the teacher is one of those who to the mountain village to help the children there.
A. have sent
B. has sent
C. has been sent
D. have been sent
网友回答
A. have sent
B. has sent
C. has been sent
(答案→)D. have been sent
解析：考查主谓一致。one of ...“......之一”，表示的是复数概念，当先行词是one of ...时，定语从句谓语用复数；排除B、C；当先行词是the only one of...时，定语从句谓语用单数。Those和sent是动宾关系，用被动语态，故选D。