下列属于化学变化的是（ ）
A．火柴燃烧
B．酒精挥发
C．车胎爆裂
D．冰棒融化
A、火柴燃烧的过程中有新物质二氧化碳等生成，属于化学变化；故选项正确．
B、酒精挥发的过程中只是酒精的状态发生改变，没有新物质生成，属于物理变化；故选项错误．
C、车胎爆裂的过程中只是形状发生改变，没有新物质生成，属于物理变化；故选项错误．
D、冰棒融化的过程中只是状态发生改变，没有新物质生成，属于物理变化；故选项错误．
故选A．
| 完型填空。 | |||
| Throughout history man has had to accept the fact that all living things must die. But people now live longer than they 1 .Yet, all living things still show the 2 of aging, which will eventually 3 death. Aging is not a disease, but as a person passes maturity (成熟期), the cells of the body and the 3 they form do not function as well as they 5 in childhood and teenage years. The body provides less 6 against disease and is more 7 to have an accident. A number of related causes may 8 to aging. Some cells of the body have a fairly long life, but they are not 9 when they die. As a person ages, 10 of brain cells and muscle cells decreases. 11 body cells die and are replaced by new cells. In an aging person the 12 cells may not be as workable or as capable 13 growth as those of a young person. Another 14 in aging may be changes within the cells 15 . Some of the protein chemicals in cells are known 16 with age and become less elastic (有弹性). This is why the skin of old people wrinkles and 17 . This is also the reason why old people 18 in height. There may be other more important chemical changes in the cells. Some complex cell chemicals, such as DNA and RNA, store and 19 information that the cells need. Aging may affect this 20 and change the informationcarrying molecules so that they do not transmit the information as well. | |||
| ( )1．A.would ( )2．A.function ( )3．A.lead in ( )4．A.hands ( )5．A.do ( )6．A.energy ( )7．A.likely ( )8．A.attend ( )9．A.replaced ( )10．A.a number ( )11．A. The others ( )12．A.old ( )13．A.to ( )14．A.factor ( )15．A.for themselves ( )16．A.change ( )17．A.hangs loose ( )18．A.increase ( )19．A.pass away ( )20．A.improvement | B．be used to B．effect B．give in B．feet B．has done B．protection B．probable B．contribute B．rebuilt B．the amount B．Others B．left B．for B．effect B．of themselves B．to have changed B．hangs loosely B．shrink B．pass by B．procession | C．used to C．affect C．run into C．heart C．did C．vigor C．possible C．add C．recovered C．the number C．Another C．new C．of C．reason C．themselves C．to change C．is hanging loosely C．lengthen C．pass off C．approach | D．used D．sign D．result in D．organs D．had done D．power D．alike D．devote D．surrendered D．a great deal D．Other D．other D．in D．element D．on their own D．to be changed D．is hanging loose D．decrease D．pass on D．process |