静态相对定位中，在卫星之间求一次差可有效消除或削弱的误差项为：（）。
A.卫星钟差
B.电离层延迟误差
C.星历误差
D.接收机钟差
参考答案：D
My daughter is only ___________. But you are a ______________girl. She can’t understand those passages in the newspaper.
A．five-year-old, sixteen years old
B．five years old, sixteen-year-old
C．five-year-old, sixteen-years-old
D．five years old, sixteen years old
货币计量假设包含币值稳定的假设。( )
