挤压机电机输出的功率主要消耗在（）。
A、加料段输送
B、螺杆输送段与出料段使物料向前推进
C、混炼段剪切物料使其升温
D、成型加工部位
参考答案：B, C
已知α，β，γ是三个不同的平面，α∩γ＝m，β∩γ＝n．则（ ）
A．若m⊥n，则α⊥β
B．若α⊥β，则m⊥n
C．若m∥n，则α∥β
D．若α∥β，则m∥n
,mother will wait for him to have dinner together.
A．However late is he
B．However he is late
C．However is he late
D．However late he is
