区分下列各组物质的两种方法都正确的是[ ]需区分物质方法一方法_爱下问搜题

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问题选择题

区分下列各组物质的两种方法都正确的是[ ]

	需区分物质	方法一	方法二
A.	空气和氧气	用带火星木条检验	闻气味
B.	硬水和软水	观察颜色	加肥皂水搅拌
C.	铝丝和银丝	用磁铁吸引	浸入硫酸铜溶液
D.	氢氧化钠和硫酸铵	加水溶解测pH	加熟石灰研磨闻气味

答案

答案：D

完形填空

Cars are very popular in America．When the kids are fourteen years old．They dream of having their own 16 ．Many students work after school to 17 a car．In most places 18 people learn to drive in high school．They have to take a 19 test to get a licence．Learning to drive and getting a driver’s 20 may be one of the most exciting things in their lives．For many，that piece of paper is an important symbol（象征）that they are now grown-ups．
Americans seem to love their cars almost more than anything else．People almost never go to see a doctor when they are 21 ．But they will take 22 cars to a “hospital” at the smallest sign of a problem．At weekends，people 23 most of the time in washing and waxing（打蜡）their cars．For some families it is not enough to have 24 car．They often have two or even three．Husbands need a car to go to work．Housewives need a car to go shopping or to take the children to school or 25
activities．

问答题简答题

谈谈车底架的作用。