primary stretching

• 初级拉伸

primary stretching的用法和样例：

例句

1. Petroleum coke can be used as either a primary or a secondary fuel.
   石油焦炭既可用作初级燃料也可用作二级燃料。
2. China is currently in the primary stage of socialism.
   我国正处于社会主义初级阶段。