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
，则函数
（ ）
平面，则内任何直线都与平行；
平面，则内任何直线都与垂直。