以下关于燃气的着火叙述不正确的是( )。
A．点燃是将气体燃料借助于外界热源(高温火炬、高温固体或电火花)使可燃混合气体的某一小部分着火形成局部的火焰，然后这个火焰以一定的火焰传播速度传播，使整个混合气着火燃烧
B．链锁着火是指在一定条件下，活化中心的浓度一直处于稳定状态，从而使燃料着火
C．热力着火是指在一定外界条件下，燃气空气混合物不能维持稳定加热，而温度开始以，不稳定状态上升，放热反应析出的热量来不及散给外界介质就加热可燃气体本身，使过程强化
D．自然可分为热力着火和链锁着火，工程上的着火都是热力着火
参考答案：B
| 阅读下面的短文，掌握其大意，然后从短文后各题所给的四个选项中，选择最佳选项。 | ||||
| As darkness fell, hundreds of people in the Swiss village left their houses. They were staring (注视) forward at the mountain top in the distance. It was covered with ice and snow — beautiful and dangerous. The huge mountain is called Matterhorn. Mountain climbers had 1 the top through the southern route (路线). But no one had ever dared to try a winter climbing up the northern side. But now one man was daring to try the 2 route. He was Walter Bonatti, a great mountain climber from Italy. For two days he had climbed. The village people had watched him 3 . Now they were waiting to see his signal. If he planned to 4 the next day, he would light (点燃) a green signal. A red light would mean that he was turning back. A tiny green light 5 high on the mountain side. Bonatti was not giving up! The people 6 . The next day he continued his way upward. He was so lonely and so 7 ! But he would not give up. Again that night he lit the green light. In the morning, Bonatti 8 . He could not see the top, he knew he was almost there. Though the climb was painful, he moved up. Bonatti had spent months 9 for the climb. Was the training enough? Did he have the strength and skill to climb to the top? He was finally at the top! News about his success was radioed to the world. The trip down the southern route was easy. He was warmly welcomed in the village. He had done the " 10 " and would be well remembered as a climber of all time. | ||||
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