Question

Work started this week on next season’s flu vaccine (疫苗), with experts working off forecasts about which types of the flu virus will be making the rounds. But don’t expect any improvements. Flu experts are already admitting that most vaccines will give at best basic protection, because they’re based on old-fashioned technology. It’s not a new problem, but one that the slow-moving world of drug and vaccine production seems helpless to improve upon.

Every flu vaccine is a cocktail, aimed at either three or four of the most common flu types. Flu vaccines must be recreated every year because flu viruses develop constantly in a process called antigenic drift. In February, global flu experts gather to trade notes on what viruses are circulating in different countries and to come to an agreement on which types the next vaccines should be made to target.

In recent years, flu vaccines have been based on H1N1, H3N2 and either one or two types of influenza B virus. Each of these has a “reference” type, which is used to make seed virus. Producers add the seed types to eggs and incubate (孵) them as the virus grows. Then they purify the virus, and either weaken it or kill it to make a vaccine.

Using eggs is a tricky (=difficult) and unpredictable process. Sometimes the virus doesn’t grow well in eggs, which can mean less vaccine than expected. The result is a flu vaccine that doesn’t offer much protection. “As long as we have eggs we are going to have this problem,” said Scott Hensley, a flu virus expert, “The only solution is not to depend on eggs.”

Flu is a major killer. The 2017-2018 season has been a severe one, hitting the entire U. S. with widespread influenza infection (感染) at once for weeks on end, and killing 97 children so far. Against this threat, even a less satisfying flu vaccine will definitely help. “Even when you have these mismatches it will not prevent infection but likely prevent disease severity,” said Hensley.

1.Next season flu vaccine fails to improve because ______.

A. it has offered the best protection

B. experts can’t forecast the flu types

C. it is based on outdated technology

D. experts are unwilling to respond to changes

2.According to Paragraph 2, flu experts ______ in February.

A. exchange views on the virus types next season

B. get together and make a deal on vaccines

C. sign an agreement on vaccine production

D. decide on how to circulate the viruses

3.The risk of using eggs to make vaccines may be that ______.

A. seeds are less likely to get protection

B. viruses might not be developed as expected

C. there are not enough eggs to be used

D. whether vaccines will grow is hard to predict

4.What message does the underlined sentence convey?

A. The U. S. is faced with serious flu attacks.

B. Egg-based vaccines are better than nothing.

C. There is something wrong with flu vaccines.

D. Flu vaccines can stop the disease spreading.

Answer

1.C

2.A

3.B

4.B

【解析】

本文是一篇说明文，近年来流感爆发较多，需要使用疫苗预防流感，文章介绍了流感疫苗的开发原理及可能存在的问题。

1.推理判断题。根据第一段第三句“Flu experts are already admitting that most vaccines will give at best basic protection, because they’re based on old-fashioned technology.”可知下季的流感疫苗是根据以前的技术开发的，很可能效果不好。故C项正确。

2.细节理解题。根据第二段最后一句“In February, global flu experts gather to trade notes on what viruses are circulating in different countries and to come to an agreement on which types the next vaccines should be made to target.”可知在二月份全球的流感专家都会聚在一起交换对未来流感种类的看法。故A项正确。

3.细节理解题。根据第四段前两句“Using eggs is a tricky (=difficult) and unpredictable process. Sometimes the virus doesn’t grow well in eggs, which can mean less vaccine than expected.”可知有时候病毒生长得并不好，可能会达不到期望值。故B项正确。

4.猜测句意题。根据横线前句“Against this threat, even a less satisfying flu vaccine will definitely help.”可知即使是不太令人满意的流感疫苗也会有帮助的。横线句是顺着这句的语义而来的，说明这样的疫苗总比没有好。故B项正确。