整个冲裁过程分哪几个阶段？
参考答案：
分三个阶段。弹性变形阶段；塑性变形阶段；剪裂阶段。
Germs are very small. They can ________ the human body______ the skin. [ ]
A. get up…across
B. get into…through
C. get out of…from
D. get into…across
