下列变化属于化学变化的是（ ）
A．汽油挥发
B．燃放烟花
C．活性炭吸附冰箱内异味
D．分离液态空气制氧气
A、汽油挥发，物质的状态改变，而无新物质生成，为物理变化，故A不符合题意；
B、燃放烟花：燃烧爆炸过程中，有新物质生成，为化学变化，故B符合题意；
C、活性炭吸附冰箱内的异味，无新物质生成，为物理变化，故C不符合题意；
D、分离液态空气制氧气：根据沸点的不同，得氧气，为物理变化，故D不符合题意．
故选B．
| 完形填空。 | ||||
| LIU XU was robbed (抢劫)! The 13-year-old boy was 1 home when a man suddenly jumped out from the roadside. He pulled Liu off his bike and rode away. Liu was scared, but he didn't run 2 the robber. He found a telephone and called the 3 at 110. " 4 is the priority (要务) in such a situation," Liu said, remembering what his teacher had told him in his first-aid class. "It is not safe to chase an adult who is much 5 than you." Liu is a junior student at Shenzhen Bao'an Middle School in Guangdong. His school is one of the first in China to have compulsory (必修的) first-aid education. Junior 1 students at the school 6 take the class once a week. Teenage safety has become a serious problem these days. According to a 2004 7 , about 16,000 teenagers die in accidents in China every year. Bao'an School said that the first-aid classes are to"teach students skills so that they can protect and save 8 in emergencies (紧急情况)." "The teacher told us that we should try not to go out 9 , especially at night. If someone tries to do bad things to us, we may hit their eyes or noses. Then we should quickly run into a 10 place," said Zhong Hua, a 13-year-old girl. | ||||
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