Mary along with her parents Hainan for a week and they will come back soon.A. have been

问题补充：

Mary, along with her parents Hainan for a week and they will come back soon.

A. have been to

B. has been in

C. have been in

D. has been to

答案：

A. have been to

(答案→)B. has been in

C. have been in

D. has been to

解析：根据语境可知此句的主语是Mary，是单数，故谓语动词也要用单数形式，故排除A和C。时间状语for a week意思是一周的时间是段时间，故谓语动词必须要用延续性，故选B。