焊接过程中，熔化金属自坡口背面流出，形成穿孔的缺陷称为（）。_爱下问搜题

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问题单项选择题

焊接过程中，熔化金属自坡口背面流出，形成穿孔的缺陷称为（）。

A．烧穿

B．焊瘤

C．咬边

D．凹坑

答案

参考答案：A

补全对话，情景问答

给下列的问句选择合适的答语。

( ) 1. How do you go to school?
( ) 2. Where is the library?
( ) 3. Who's she?
( ) 4. When are you going?
( ) 5. What are you going to do?

A. I'm going to buy a book.
B. I go to school on foot.
C. It's in front of the school.
D. She's my aunt.
E. This afternoon.

单项选择题

下面哪种情况应禁用β受体阻断药

A．心绞痛

B．A-V传导阻滞

C．快速型心律失常

D．高血压

E．甲状腺功能亢进