采用测距码测定的卫星至接收机的距离，由于受到（）此被称为伪距。
A.卫星钟差
B.接收机钟差
C.大气延迟
D.上述所有项
参考答案：D
We believe governments will a better way to solve the problem of water pollution.
A．take off
B．put off
C．come up with
D．catch up with
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