题干
—Where is your mother?
—She ______ Australia and she ______ Sydney for two weeks.
A：has been to; has been in
B：has been to; has been to
C：has gone to; has been in
D：has gone to; has been to
答案(点此获取答案解析）
C
= (1，1)，
= (1，－1)，
=(－1，2)，则