近似值7.3与7.30大小相等,表示的精确度也相同。[ ]

题型:判断题

问题:

近似值7.3与7.30大小相等,表示的精确度也相同。[ ]

考点:求小数的近似值
题型:判断题

某兴趣小组同学对废干电池筒内黑色固体进行探究.

查找资料得知:

①废干电池内含有Mn02、NH4Cl、ZnCl2等;

②NH4Cl具有铵态氮肥的性质;

③向ZnCl2溶液中逐滴滴入稀氨水,先生成Zn(OH)2白色沉淀,然后沉淀溶解,生成可溶性的[Zn(NH34]Cl2

据此,该兴趣小组同学进行了如下探究:

(1)检验Mn02的存在.兴趣小组同学设计了如图所示的实验:

操作②的名称是______,该操作中玻璃棒的作用是______.

操作③灼烧黑色滤渣时,会产生一种能使澄清石灰水变浑浊的气体,该气体为______.

操作④的试管中产生的气体能使带火星的木条复燃,该气体为______.

由此得出结论:滤渣中除含有______外,还含有黑色粉末______.

(2)猜想1:滤液中溶质的主要成分为NH4Cl.

操作:取少量滤液加入盛有NaOH固体的试管,并加热.未闻到明显的刺激性气味,但用紫色石蕊试纸放在试管口一段时间,试纸变蓝色.

实验结论:该滤液中含有少量的NH4Cl.

(3)猜想2:滤液中溶质的主要成分为ZnCl2.向盛有少量滤液的试管中逐滴加入______,观察到______.

实验结论:滤液中溶质的主要成分是ZnCl2

题型:判断题

.

Besides relevant theories and keen logic, a scientist who does research in economic psychology and who wants to predict the way in which consumers will spend their money must study consumer behavior.  It’s vital for his credit as a qualified economist.   He must obtain numbers and material both on the resources of consumers and on the efforts that tend to encourage or discourage money spending.

If an economist were asked which of the three groups borrow most——people with rising incomes, stable incomes or declining incomes——he would probably answer: those with declining incomes.  Actually, in the past 5 years, the answer was: people with rising incomes.  This shows us that traditional assumptions about earning and spending are not always reliable.  Another traditional assumption is that if people who have money expect prices to go up, they will hurry to buy.  If they expect prices to go down, they will postpone buying.  But research surveys have shown that this is also not always the case.  Their expectations of price increases may not stimulate buying.  One typical attitude was expressed by the wife of a mechanic in an interview at a time of rising prices.  “In a few months,” she said, “we’ll have to pay more for meat and milk.  We’ll have less to spend on other things.”  Her family had been planning to buy a new car but they postponed this purchase.  Furthermore, the rise in prices that has already taken place may be hated and buyer’s resistance may be caused.  This is shown by the following typical comment of the wife: “I just don’t pay these prices: they are too high.”

Traditional assumptions should be investigated carefully, and factors of time and place should be considered.  The investigations mentioned above were carried out in America.  Research conducted at the same time in Great Britain, however, produced results that were more in agreement with traditional assumptions about saving and spending patterns.  The condition most beneficial to spending appears to be price stability.  If prices have been stable and people have become accustomed to considering the current prices “right”, they are likely to buy.  Thus, in a society of good economy which maintains consumer confidence, it appears that the common business policy of maintaining stable prices with occasional sales or discounts is based on a correct understanding of consumer psychology.

72. According to the passage, it is essential for a successful economist to ______.

A. know about economic theories 

B. be capable of logical thinking

C. predict the latest national economy

D. to understand consumers’ spending habits

73. The example of the mechanic’s wife is intended to show that ______.

people tend to buy more when prices are expected to fall

people tend to buy less when prices are expected to fall

people tend to buy more when prices are expected to rise

people tend to buy less when prices are expected to rise

74. Findings in investigations in Britain show _____.

consumer behaviour may vary in different places

Britain and America share similar saving and spending patterns

Britain is important in economic research

occasional discounts and sales are important

75. According to the passage, what is most helpful in promoting spending?

A. Big discount.     .      B. Good consumer confidence.

C. Steady price.            D. Positive consumer psychology.

题型:判断题
如图表示一交流电的电流随时间而变化的图象,此交变电流的有效值是(  )

A.5A

B.5A

C.3.5A

D.3.5A

题型:判断题

材料中体现出雅安市人民代表大会与雅安市政府的关系是

A.互相监督、分工合作的关系

B.监督与被监督的关系

C.立法机关与行政机关的关系

D.领导与被领导,上级和下级关系

题型:判断题

英汉互译

1. 他比我大四岁。     

                                      

                                    

2. Senior students need not wear school uniforms.    

                                    

3. He is your senior by two years.   

                                     

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