压力容器安全等级由最高工作压力、容积和()几个方面确定的。
A.介质
B.材料种类
C.结构
D.制造方法
参考答案:A
选择下列问句的正确答语,将序号填入括号里。
1. What's he doing?[ ]
A. He is at home.
B. He eats dinner.
C. He is picking up leaves.
2. Is she collecting leaves?[ ]
A. Yes, he is.
B. No, she isn't.
C. No, she doesn't.
3. Is she writing a report?[ ]
A. No, she isn't. She's writing a letter.
B. Yes, I am.
C. No, he isn't.
缝口的形式、线迹的形式、缝料的性能、缝纫线的性能、缝料在缝制中的损伤、()等是影响服装缝口强度的主要因素。