在容易自燃和自燃的煤层中掘进巷道时，对于巷道中出现的冒顶区，为什么必须及时进行防火处理？
参考答案：
一是冒顶区孔洞、极易堆积大量可燃性碎煤；二是冒顶区孔洞、虽处于巷道风流流动的边缘地带区、，但受风流流动扩散作用和影响，仍可能有部分风流流入其中，为煤炭氧化自燃提供足够的氧气；三是有一个较为稳定的蓄积热量的环境条件。由于上述这3个条件同时存在于冒顶区孔洞、中，自然发火也就必然发生。许多矿区矿、发生的事故也证明了这一点：凡是煤层巷道的冒顶区孔洞，不采取有针对性的专项防火措施进行及时处理，就是一个发火点。
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| In the United States, Monday is the beginning of the workweek(工作周). It is the day most Americans like __1__. And it is certain that the day they like most is Saturday. Saturday is the __2__ of the workweek, and it is the beginning of the weekend. Life is __3__at weekends. Most Americans take care of their houses, cars or gardens. They __4__ the feeling that time seems to move slowly. The workweek is for things you have to, but the __5__is for things you want to do. Some people may get in a car and go for a __6__ in the country. They like to take part in outdoor activities. They __7__ go to a public eating or a film on Saturday night. The __8__ of weekends is a recent invention(近期的发明). In the 1870s, rich people began to speak of __9__ weekends in the country visiting friends. For most people, however, the workday was six days __10__ .
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