—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
人突然从低海拔处上升到高海拔处,鼓膜会感觉不适,可通过做咀嚼运动或大口呼吸等来缓解,原因是( )
用分数表示
用小数表示
用复名数表示
3 15 千米
____
3.05吨
3分45秒
关于摩擦力的说法正确的是( )