细胞外铁阴性，铁粒幼红细胞占12％，此结果符合（） A.正常骨髓铁粒染色 B.缺铁性

根据短文内容，从短文后的七个选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

                                                   Are Societies Ageing Too Fast?

     An ageing society is one in which the population of people over the age of 60 is increasing. The global

population at present is about 6 billion with l person in every 10 aged 60 or above. 1._____ This will mean

that for the first time in human history the population of older persons will be larger than the population of

children! What are the causes of this population change?

     2._____ And another is that birth rates have dropped as people, especially women, are educated. Measures

to slow population growth like China's one-child policy, have also contributed to lowered birth rates. The

increase in the aged population is not just an interesting trend, however; it also has severe implications for the

future of global economies.

     People traditionally retire at 65 and live on government pensions. 3._____ Another concern is that as medical

expenses increase with age, the demands of the growing aged population will eventually cause medical systems

to face bankruptcy (破产).

     4._____ They suggest that because people are living longer, they ought to work longer, while governments

need to establish a sound social security system. They also suggest that individuals start saving as soon as

possible to ensure a financially secure retirement. People should also develop good health habits in their youth

to ensure an active and productive old age. 5._____ By finding cures for diseases like Alzheimer's and cancer,

medical bills and the need for care would be drastically reduced.

     Finally, an important step to ensure a bright future for all is to do away with negative stereotypes that see

valuable members of society only as pensioners or patients. It's high time we stopped seeing ageing as a disease

and started playing our parts in securing the future of our ageing societies.

A. Due to ageing problem, cities are facing more challenges.

B. Experts insist that steps should be taken now to prepare for the future.

C. As people grow older, a huge financial burden will be placed on the government.

D. Biomedical research is another tool we can use to deal with the problems of ageing societies.

E. One reason is that dramatic health advances have added 20 years to the average life expectancy.

F. The United Nations projects that by 2050, it will be l in every 5.

G. As is known to all, good habits lead to good health.

为研究甲、乙两种培养基的生长效果是否相同，将100份标本的每一份一分为二，分别接种于甲、乙培养基，所得结果为：甲、乙培养基均生长的有30份，甲生长、乙不生长的25份，甲不生长、乙生长的35份，甲、乙均不生长的10份。据此资料与研究目的（）

A.宜将资料整理成下表后作四格表χ²检验

B.宜将资料整理成下表后作成组设计四格表χ²检验

C.宜将资料整理成下表后作成组设计四格表χ²检验

D.宜将资料整理成下表后作成组设计四格表χ²检验

E.宜将资料整理成下表后作配对设计四格表χ²检验

对于一些褶皱比较紧，牵拉时容易撕裂的部分，可适当加热。目的仅是为了消除变形的应力，使之松弛。

（）是北宋著名诗人宋祁的名句。

A．绿杨烟外晓寒轻，红杏枝头春意闹

B．春风又绿江南岸，明月何时照我还

C．沙上并禽池上暝，云破月来花弄影

D．停车坐爱枫林晚，霜叶红于二月花

在文献的选择上应注意什么问题？