问题 选择题

下列变化中,一定发生了化学变化的是(   )

A.酒精挥发

B.滴水成冰

C.粉笔折断

D.食物腐败

答案

答案:D

题目分析:A 酒精挥发属于酒精的三态变化之一,没有新物质生成,为物理变化;B滴水成冰属于水分子排列方式发生了变化,无新物质生成,为物理变化;C 粉笔折断没有新物质生成,为物理变化;D 食物腐败涉及诸多化学反应,有新物质生成,为化学变化。

点评:物理变化和化学变化的判别向来是中考的必考点,常在单项选择题里面比较靠前的位置出现,属于简单题。

单项选择题
改错题

短文改错(共10小题;每小题1.5分,满分15分 )

此题要求对一段文章改错。先对每一行做出判断是对还是错。如果是对的,在该行右边横线上画一个勾(√);如果有错误(每行不会多于一个错误 ),则按情况改错如下:

此行多一个词,把多余的词用斜线(﹨)划掉,在该行右边横线上写出该词,并也用斜线划掉。

此行缺一个词,在缺词处加一个漏字符号(∧),在该行右边横线上写出该加的词。

此行错一个词,在错的词下划一横线,在该行右边横线上写出改正后的词。

注意:原行没有错的不要改。

Most Americans would find it hard to think that what life   小题1:____________

would look like without a car. But, some have realized    小题2: _______ ____

the serious question of the pollution caused by the car.  小题3: ____ ________

The polluted air becomes harmful and dangerous to health.  小题4: ___ ________

One way to getting rid of the polluted air is to build a   小题5:____________

car that doesn’t cause pollution. That is how several of the  小题6: ____  ______

large car factories have been tried to do. But to build       小题7: _________   

a clean car is more easier said than done. Progress in this   小题8:_________   

field has been slow.

Another way is to take place of the car engine by a     小题9: ___________ 

steam one. Inventors are now working on steam cars as well as

electric cars. Many makers believe that it will spend         小题10: __________  

years to develop a practical model that pleased people.