GPS网的同步观测是指( )。

A．用于观测的接收机是同一品牌和型号

B．两台以上接收机同时对同一组卫星进行的观测

C．两台以上接收机不同时刻所进行的观测

D．一台收机所进行的两个以上时段的观测

Some people argue that university education should be made _____ to most people, not only to good students. [ ]

A. available

B. considerable

C. varied

D. extinct