问题 单项选择题

研究人员研发出了一个将年龄因素考虑进去的流感传播的数学模型。他们确信,当今的一场流感流行可以通过最佳地分发6300万剂的疫苗而使其中止,即把5—19岁的孩子(他们是造成大多数传播的原因)和30—39岁的成年人(他们是最容易从他们的孩子那里感染到流感的人)作为首要的疫苗接种标靶人群。他们说,这一标靶疫苗接种可转而帮助保护其他的人群不受感染。此外,该模型所预测的6300万剂疫苗比目前每年对季节性流感所接种的8500万剂疫苗要少。
这个研究结果主要表明______。

A.分配疫苗要考虑与年龄有关的传播模式
B.数学模型在人类疾病研究方面具有重要作用
C.流感的易感人群主要集中在5—19岁和30—39岁两个年龄段
D.流感疫苗的成本完全可以降低

答案

参考答案:A

解析: 文段首句提到了这一研究针对的是流感传播与年龄的关系,具体目的通过文段其余内容可以得出,即年龄对流感传播有重要影响,在流感疫苗分配时要关注这些影响,可以减少现在的疫苗投放量。因此本题正确答案为A项。研究只是借助数学模型这个工具对流感进行分析,并不能得出B项说法;C项流感的易感人群范围并非文段主旨;根据文段的说法是可以减少流感疫苗的接种数量,但“成本”问题文段并没提到,D项不入选。

阅读理解

阅读理解。

      The nervous-looking (紧张不安地) young man had waited for a few moments outside the jeweler's shop

before he got enough courage (勇气) to enter. He was warmly greeted by a young assistant. James felt a rush

blood to his face as he explained he would bring in his future wife to choose a birthday present. The assistant

listened carefully and told him he'd better buy a necklace. He wasn't used to buying jewelry and was a little

worried about overspending. After some discussion as to reasonable price and type, the assistant showed him

dozens of necklaces and helped him to choose. At last James chose one and left the shop promising to return

at five o'clock. When, half an hour later, James did return to the shop with his future wife, Laura, the assistant

acted as if she had never seen him before. When she was asked to show them some necklaces, she first

brought out some inexpensive ones for them to choose and then gave them the one she had prepared. A choice

was soon made and they went away, satisfied. James would certainly come back to buy what he wanted when

he got married.

1. A good title for this passage is _____. [ ]

A. A Clever Assistant

B. Buying a Birthday Present

C. How to Choose a Necklace

D. A Brave Young Man

2. The word "overspending" in this passage means _____. [ ]

A. spending too much money

B. spending too much time

C. spending more time than be planned

D. spending too much time and too much money

3. When James told the assistant why he wanted to buy a present, his face _____. [ ]

A. turned pale   

B. turned red

C. turned yellow   

D. turned black

4. James would come back to buy what he wanted because _____. [ ]

A. the assistant knew how to satisfy the people who came to buy things

B. the necklace was good

C. Laura liked the necklace

D. the assistant who served James was very beautiful

多项选择题