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SAT阅读主旨类题目解题技巧

2016-09-18 12:44

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主旨题考查对文章中心思想的理解。回答主旨题,一种方法是先回顾文本大意、每段大概内容或者文章中反复重申的主题。然后选出相对应的选项。或者采用排除法,剔除错误选项。过程中注意两点:


以下就是100留学为大家带来的SAT阅读主旨类题目解题技巧,希望对各位的备考有所帮助:


一是要基于文本,而不是自己想当然。所以可以排除文章未提到的内容或者根据文章进行衍生的内容。例如:一篇表达科技是好东西的文章并不一定意味着作者认同科技是解决问题最好的方法。一定要警惕某些选项中的观点用力过猛,不符合文章本意。

二是该选项表达的内容至少适用于概括文章的大部分。也就意味着,做主旨题,不能将注意力放在文章的细节上,而是大意上(big picture)。有些选项呈现的只是文章的细节内容,不足以成为文本大意。故要选择在整个文本中深入讨论或在各段多次重申的选项内容。


主旨题的出题形式大致如下:

Thepassage primarily focuses on?

Thepassage is primarily concerned with?

The mainpurpose of the passage is to?

等等。


请看一例:

This passage is adapted fromLynne Peeples “Moths Use Sonar-Jamming Defense to Fend Off Hunting Bats.” ©2009 by Scientific American


Aninsect with paper-thin wings may carry much the

same defense technology as some of themilitary's heavy-

duty warships. The finding that a species oftiger moth can

jam the sonar of echolocating bats to avoidbeing eaten

seems to be the "first conclusive evidenceof sonar jamming

in nature," says Aaron Corcoran, a biologyPhD student at

Wake Forest University and the lead author ofthe paper

reporting the discovery. "It demonstratesa new level of

escalation in the bat–moth evolutionary armsrace."

Before Corcoran's study, scientists werepuzzled by why

certain species of tiger moths made sound. Somespeculated

that the moths use it to startle bats. A fewpointed to its

potential interference with their echolocation.General

consensus, however, fell with a thirdhypothesis: clicks

function to warn a predator not to eat theclicking prey

because it is toxic, or at least pretending tobe.

To test these hypotheses, Corcoran and his teampitted

the tiger moth Bertholdia trigona against the big brown

bat Eptesicusfuscus, a battle frequently fought after

sundown from Central America to Colorado.High-speed

infrared cameras and an ultrasonic microphonerecorded the

action over nine consecutive nights. Theprocess of

elimination began. If moth clicks served tostartle, previous

studies suggested the bats should becometolerant of the

sound within two or three days. "Butthat's not what we

found," says Corcoran, explaining the lackof success bats

had in capturing their clicking prey eventhrough the last

nights of the study.

How about the toxic warning theory? If thiswere the

case, according to Corcoran, bats would notfind the

moths palatable or, if they were indeed tasty,they would

quickly learn they'd been tricked. Either way,bats should

start to ignore the moth's unique ultrasonicclicks. Also, bats

partook readily when offered B. trigona that lacked the

ability to click, and they kept coming back formore. This

attraction also held true for clicking B. trigona: The

predators persisted after their prey despiteonly reachinghem about 20 percent of the time. Bats actually launched

four times as many successful attacks against acontrol group

of silent moths. These findings are "onlyconsistent with the

jamming hypothesis," Corcoran notes."But the most

distinctive evidence was in the echolocationsequences of the

bats."

Normally, a bat attack starts with relativelyintermittent

sounds. They then increase in frequency—up to200 cries per

second—as the bat gets closer to the moth"so it knows

where the moth is at that criticalmoment," Corcoran

explains. But his research showed that just asbats were

increasing their click frequency, moths"turn on sound

production full blast," clicking at a rateof up to 4,500 times a

second. This furious clicking by the mothsreversed the bats'

pattern—the frequency of bat sonar decreased,rather than

increased, as it approached its prey,suggesting that it lost its

target.

The biological mechanism behind the moth'sdefense

strategy is still unclear to researchers."Most likely, moth

clicks are disrupting the bat's neuralprocessing of when

echoes return," Corcoran says. Bats judgehow far away a

moth is based on the time delay between makingthe cry and

its audible return. This "blurring"of the bat's vision, he

explains, "may be just enough to keep themoth safe."


题目:

The passage is primarily concernedwith

(A) the ways Eptesicus fuscus bats capture moths.

(B) the discovery that tiger moths can jambats’ sonar.

(C) how the tiger moths’ clicking defenseworks.

(D) why tiger moths developed defenses againstbats.

解析:主旨题的解答也涉及到对文章大意的理解。我们先看下文章的大意脉络。

第一段引出新的发现:一种tiger moth可以通过干扰蝙蝠的声纳定位系统避免被捕食。

第二段展示传统的观点:被捕食者发出干扰信号,让捕食者误以为它们有毒,从而避免被捕食。

第三段展示实验过程,验证新的发现。

第四段反驳传统观点。

第五段展示tiger moth干扰蝙蝠声纳定位系统的表现形式。

第六段猜想。


故根据对文章大意脉络的梳理,我们可以知道选项B正确。选项A强调蝙蝠捕捉飞蛾的方式,文章探讨的是tiger moth如何避免被捕食。选项C不符,选项C概括了第五段的内容,不足以概括全篇。选项D强调原因。文本强调的不是原因,而是机理。


选项B正确。

以上就是100留学为大家带来的SAT阅读主旨类题目解题技巧,更多SAT阅读考试技巧备考内容,请继续关注100留学。


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(文章内容摘选自
《新SAT非官方指南》

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