We ran down to the shore in time to see an enormous animal opposite us _____itself out of the water and then _____ down again, which was a whale..

A．thrown; crashing

B．throwing; crashed

C．throwing; crashing

D．thrown; crashed

国家基本平面控制网，采用三角测量方法而建立的称为国家三角网，随着GPS测量技术的发展，建立了高精度的（）。