两道关于现在完成时的选择题—these farmers have been to the united states —

两道关于现在完成时的选择题
—these farmers have been to the united states —really?when____there?
A. will they go B.did they go C. do they go D,have they gone
(选的是B,原因?)
My parents _____handong for ten years
A.have been in. B.have been to C.have gone to D,have been
(选的是A,原因?）