筛分过程的技术经济指标是（）
A、筛分效率
B、筛分效率与生产率
C、生产率
D、总效率
参考答案：B
On April 10, 2010, the Polish presidential plane did not ________ to the runway while landing. It hit the treetops and fell apart.
A．take it
B．make it
C．get it
D．put it
辊式矫直机的辊数增加有利于提高矫直精度。
