问题补充：
–– My father Shanghai with my grandparents.
––Really? will they come back?
A. has been to; How soon
B. has gone to; How soon
C. has been to; How long
D. has gone to; How long
答案：
A. has been to; How soon
(答案→)B. has gone to; How soon
C. has been to; How long
D. has gone to; How long
解析：How soon 多久，一般对将来时间进行提问；How long多长，一般对时间长短进行提问。句意：我的父亲和我的爷爷奶奶去了上海。——真的吗？他们多久回来？在完成时态中has been to 是已经去过某处，并且已经回来了。has gone to 是已经去了某处，但是到目前为止还没有回来。结合语境可知选B。
