光固化封闭剂常用的可见光光源波长为（）。 A．230～290nm B．330～390

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问题单项选择题

光固化封闭剂常用的可见光光源波长为（）。

A．230～290nm

B．330～390nm

C．430～490nm

D．530～590nm

E．590nm以上

答案

参考答案：C

补全对话，情景问答

补全对话。

A: Excuse me. What day 1_____ yesterday?

B: It was Sunday.

A: 2_____ you very busy?

B: Yes, I was very busy.

A: What 3_____ you do?

B: I did my homework first. Then I 4_____ to the park with my parents.

A: How did you go there?

B: By bus. We 5_____ a good time in the park.

A: Where did you have lunch?

B: In the park. We had milk and bread for lunch.

单项选择题

凡介质含有固体悬浮物，需考虑耐磨问题，衬里管道可采用厚2mm( )作底层，再用( )做面层的复合衬里。

A．铜管软橡胶

B．铜管硬橡胶

C．硬橡胶软橡胶

D．软橡胶硬橡胶