Our teacher told us that _______ moon moves around ______ earth, and

________ earth circles________ sun.

A．a, a, a, a

B．an, an, an, an

C．the, the, the, the

D．/, /, /, /

由接触位置改变所引起的误差，对点接触来说是（）。

A.一次误差

B.二次误差

C.三次误差