问题补充：
---Where is your grandpa?
---He Canada and Toronto for a month.
A. has been to, has been in
B. has gone to, has been in
C. has been in, has been to
D. has gone to, has been to
答案：
A. has been to, has been in
(答案→)B. has gone to, has been in
C. has been in, has been to
D. has gone to, has been to
解析：句意:--你的祖父在哪里？--他去加拿大了，他要在那里停留一个月。has been to表示去过某地，但是现在已经回来了；has gone to表示去了某地还没有回来；has been in表示在某地停留，后面可以跟时间段。根据for a month可知第二空应该用has been in，根据句意故选B。
