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问题 单项选择题

窒息、冷却、辐射及对有焰燃烧的化学抑制作用是干粉灭火效能的集中体现，其中()作用是灭火的基本原理，起主要灭火作用。P60

A.窒息

B.冷却

C.辐射

D.化学抑制

答案

参考答案：D

问答题

简述行为改变的基本方法。
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单项选择题

Questions 24-30


·Look at the questions for this part.
·You will hear a passage about "Marriage Customs in the U.S. ". You will listen to it twice.
·For questions 24-30, indicate which of the alternatives A, B, or C is the most appropriate response.
·Mark one letter A, B, or C on the Answer Sheet.

The use of a ring from the ancient custom means ______.

A．to establish an important agreement.

B．to show respect to marriage.

C．to show the financial condition of the bridegroom.
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