如何快速準確抓住科普類說明文的主旨

在高中英語閱讀中，考生由于知識的局限性和詞匯量不大，科普類說明文相對較難。而主旨大意題本身又是考生最畏懼的題型，所以很多時候，考生對科普類說明文的主旨題都是瞎蒙一通。筆者現(xiàn)在把自己摸索出來的規(guī)律談一談，希望對廣大考生有所幫助。

筆者在科普類說明文中發(fā)現(xiàn)，一般的科普類說明文整體可分兩部分。我把它們稱之為finding（結(jié)論部分）和 experiment（實驗部分或如何得出結(jié)論的過程）。主旨大意題的答案一般由finding部分而來，finding通常在第一段中。我們可通過一些練習(xí)來驗證這種方法。

[例1]2010—2011學(xué)年《學(xué)生雙語報》第33期閱讀B版B篇:

Scientists recently reported on a disgusting new idea for human health: The ground-up brain of cockroaches， they say， may help fight infectious diseases.

…

The scientists decided to study insects after noticing an interesting pattern. Some soldiers who came back from the Middle East were sick with strange infections—but locusts(蝗蟲) from the same areas were infection-free. Locusts are types of grasshoppers. The scientists started to wonder how insects that live in unclean places manage to avoid infection.

To find out， the researchers ground up different parts of locusts and cockroaches and put the mixtures in Petri dishes with types of the harmful bacteria. Ground-up tissue from cockroach and locust brains and locust nerves， however， killed almost all the harmful bacteria—nearly 100 percent. That means that the bug brains and nerves must contain chemicals that kill the bacteria.

…

問題：The main idea of the passage is that __________.

A. cockroaches ate nasty animals

B. cockroaches could be good medicine

C. cockroaches bring new infectious diseases

D. cockroaches can be good to the environment

我們可以看到，第一段就是finding，一個新發(fā)現(xiàn)的結(jié)論；后面的段落為experiment部分。所以答案是B。

[例2]2010—2011學(xué)年《學(xué)生雙語報》第33期閱讀C篇：

A new technique that lowers blood pressure by blasting the kidneys with radio waves could “revolutionize” treatment， a study claimed yesterday.

…

問題：What’s the best title for this passage?

A. A promising study on radio waves.

B. A significant risk factor for heart attacks.

C. High blood pressure can be cured by different drugs.

D. High blood pressure can be treated with radio waves.

答案是D。

[例3]2010—2011學(xué)年《學(xué)生雙語報》第36期閱讀A篇：

Polar bears， considered doomed if the Arctic sea ice continues to melt， have a fighting chance at survival if humans cut back on their emission of greenhouse gases， according to a new study.

…

問題：What’s the main idea of this passage?

A. Arctic ice will disappear in less than a decade.

B. Arctic sea ice is important to polar bears’ survival.

C. Ploar bears will soon disappear if the Arctic sea ice continue to melt.

D. Ploar bears can survive if humans reduce the emission of greenhouse gases.

答案是D。

通過以上練習(xí)，我們可以發(fā)現(xiàn)：科普類說明文主旨大意題的答案一般可以在finding部分快速找到。在第一段我們通常可以找到 A study / scientists... reported， claimed， showed， proved... 等關(guān)鍵字眼和表達，它們的前或后就是finding（結(jié)論部分），即科普類說明文主旨大意題的答案所在。

(作者單位：江門開平市第一中學(xué))

責(zé)任編校蔣小青

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