Look! The duck is swimming ____________ the lake.[ ]
A. in
B. at
C. near
答案：A
压片时造成粘冲原因的错误表达是
A．压力过大
B．冲头表面粗糙
C．润滑剂用量不当
D．颗粒含水量过多
E．颗粒吸湿
什么是轮对空心轴二级弹性驱动装置？
