航海学中的地球形状用（）来描述。
A．地球自然表面围成的几何体
B．大地球体
C．地球椭圆体
D．以上都对
参考答案：B
埋弧焊时，如果焊件清理不干净，焊缝容易产生（）。
It is not enough to ensure that the suppliers provide value for money; the governmental buyer must enter into a dialogue with the suppliers to ensure as far as possible that the form of the procurement is persisted to the enhancement of the supply industry’s global competitiveness.
A．cooperative with
B．consistent with
C．cooperative in
D．consistent in
