挤出机的分类方法很多，按挤出成型原理可分为柱塞式、螺杆式和无螺杆式挤出机。
参考答案：对
（）是流动资产中最重要的组成部分，常常达到流动资产总额的一半以上。
A.现金
B.存货
C.利润
D.股票
Mr Li is a good teacher. He always makes his class _____.[ ]
A. lively and interested
B. lively and interesting
C. alive and interested
D. alive and interesting
