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什么叫火焰的传播？

答案

参考答案：

当点燃一部分燃气-空气的混合物时，在着火处形成一层极薄的燃烧焰面，这层高温焰面加热了相临的燃气-空气混合物，使其温度升高，当达到着火温度时就开始着火形成新的焰面，这样焰面就不断向未燃气体方向移动，使每层气体都经历加热、着火、燃烧的过程，这个现象称为火焰的传播

听力题

根据短文内容完成下列句子，每空一词。

This is a picture of Mr. Black's family. The man is Mr. Black. The woman is Mrs. Black. They have a son and a daughter. The son is behind Mr. Black. He looks like his mother. His name is Mike. He's thirteen. Their daughter, Ann is behind Mrs. Black. She is eleven. Mike and Ann are in the same school. But they are not in the same grade. Mike is in Grade Nine. Ann is in Grade Seven. They are good students at school. Mike likes English, but he doesn't like math. Ann likes Chinese and math. She also likes singing English songs.

小题1:Mr. Black has          children.

小题2:The son is behind Mr. Black. His name is      

小题3:Ann is          years old.

小题4:Mike and Ann aren't in the same        

小题5:Ann likes        , but Mike doesn't like it.
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多项选择题

忠诚所属企业的主要表现是（）

A、诚实劳动

B、关心企业的发展

C、做到举止得体

D、遵守合同契约
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