用为:不超过按元/收费,超过的
4.某铁路客运部门规定甲、乙两地之间旅客托运行李的费
3.已知,,,则的大小关系是
充分必要条件 既不充分也不必要条件
充分而不必要条件 必要而不充分条件
2.设集合且,,那么“”是“”的
A. B. C. D.
1.已知是虚数单位,则
10. My brother ____college for over three years.
A. has gone to B. has been to
C. has been in D. has been at