All of the flowers now raised here have developed from those _______ in the forest.

A．once they grew

B．they grew once

C．they once grew

D．once grew

由于系统误差和（）对船位的影响不同，两者对船位线交角（即方位差）的要求也不一致。

A.曲率误差

B.粗差

C.系统误差

D.随机误差