Most museums are just for looking. But today some of them have things for you to touch.The ＿＿say,“＿＿”

A．signs; Do touch

B．notices; To touch

C．signals; Be touching

D．signs; No touching

影响角度放样精度的主要有（）。

A、仪器对中误差

B、目标偏心误差

C、仪器误差

D、操作者的失误