英语六级阅读模拟训练附答案讲解

　　You’re likely already familiar with Dolly—the sheep that achieved near _2_ status as the firstmammal to be cloned successfully using adult animal cells. But Dolly is not alone. The world'sfirst clone—a tadpole—was actually created as early as in 1952. And at least a dozen differentspecies have been cloned since: everything from the common cow to the _3_ guar, a type ofwild ox.

　　Animal cloning has come a long way since that first tadpole more than 50 years ago. The U.S.Food and Drug Administration's (FDA) declaration in early 2008 that food products _4_ fromthe clones of cows, pigs and goats are safe for human consumption _5_ an already growinginterest in the process.

　　Cloning may have _6_ uses besides its ability to help farmers _7_ breed quality burgers andbacon. Other potential uses _8_ the preservation of species, biomedical research, drug andorgan production and even commercial ventures.

　　It seems that finding out exactly how many cloned animals have been produced is almost asdifficult as producing them in the first place. There’s no official _9_ of clones, and laboratoriesaren't required to report every single tadpole or mouse they create. But armed with a bit ofknowledge concerning animal cloning and its _10_, it’s likely to narrow down the contestants toa possible field.

　　A) inclusive B) derived C) applications D) actually

　　E) additional F) intensified G) visualized H) celebrity

　　I) include J) typically K) compromise L) endangered

　　M) registry N) duplicates O) consistently

　　解题思路

　　1.[D]空格前后分别为句子的主语和谓语，因此空格应为副词。前一句中的half right表明本句将要说出“真正的”答案，故选actually，说明上文提到的那些名字“事实上”是几种克隆动物的名字。

　　2.[H]空格应为形容词、名词或分词，作定语修饰status。上文提到的几种克隆动物的名字不太为人所熟悉，而这里所讲的多利羊(Dolly)很多人知晓(familiar)，故此处选用celebrity，表明多利羊“很出名”。

　　3.[L]空格在定冠词和名词之间，为修饰名词的定语。From…to…结构表明空格最有可能是形容词，这样the...guar形式上才能与the common crow—致。该句前面提及很多不同物种被克隆了，其后举例加以说明， 由此推断此处应该是从“普遍”到“特殊”的列举，endangered符合语义。

　　4.[B]空格位于that引导的从句中，从句的主语是food products,谓语是are safe,可见空格应该是修饰foodproducts的后置定语。from the clones of...表明填人空格的词应表示某种动向且能与from搭配，最可能是过去分词。derived符合句意，表明“源自克隆牛、克隆猪和克隆羊的食物可以安全食用”。

　　5.[F]通过分析句子成分可知，空格是主句的谓语，与an already growing interest构成动宾搭配，其主语是declaration。in early 2008提示谓语动词为一般过去时。动词库中intensified“增强”能与interest;构成动宾搭配，填入空格句意通顺。

　　6.[E]空格在名词uses之前，作其定语。下一句提到克隆技术可能用于保存物种、生物医学研究等，可知这一技术除帮农民生产出汉堡包和熏猪肉外，还有其他用途。additional符合句意。

　　7.[O]空格在动词词组help... breed之间，应为副词。本段讲克隆技术的好处，故填入的副词应包含积极意义，consistently符合语境，表示“源源不断地”生产出髙质量的汉堡包和熏猪肉。

　　8.[I]空格处应为动词，作句子谓语。主语为other potential uses，宾语为克隆技术应用的各领域，词库中动词include “包括”符合此处句意。

　　9.[M]空格位于no和介词of之间，应为名词，且被official修饰。本句解释难以确切知道有多少克隆动物的原因，此处指出其中一个原因“没有关于克隆的官方……”，registry符合句意。

　　10.[C]空格在形容词性物主代词its后，应为名词。本句说的是找到更多克隆动物的方法，那就要具备这方面的相关知识，此处应选用applications，填人文中意为“只要掌握一点关于克隆及其应用的知识，就能缩小找寻被克隆的动物的范围”。

　　It’s a good idea to apply sunscreen before heading to the beach if you don’t want to bum. Butfor marine animals like whales，they don’t have that _1_. Species like sperm whales can spendup to six hours at the ocean’s surface in between dives, _2_ in the sunlight. So how do theyprotect themselves from a serious case of sunburn?

　　It turns out that their bodies have a similar defense _3_ against the sun’s UV radiation aspeople. Blue whales—which have the lightest skin color of the three species—tan during theirsummer stay before _4_ back to their northern feeding grounds. Sperm whales don’t tan. Theycan receive an “overdose” of UV radiation during their hours at the ocean’s surface, and theyhave proteins that _5_ protect their cells from UV damage. This process is _6_ to how humanbodies produce antioxidants in response to molecules that can cause a lot of genetic andcellular damage. And fin whales escape sun damage thanks to their high levels of melanin—adark substance in the skin to protect humans from UV radiation.

　　Older whales and whales with less _7_ of melanin in their skin—like blue whales—had thegreatest level of damage in their mtDNA. Fin whales, which had the greatest amount of melanin,had the least amount of mtDNA damage.

　　Now that the ozone layer that shields Earth from UV radiation is gradually _8_, it’s importantto know what the consequences are for whales and dolphins, especially for _9_ or endangeredspecies. Although it’s difficult to tell what causes many of these skin conditions, UV damage isone cause. Even though whales have _10_ defenses to UV radiation, high exposure can stillbe harmful.

　　A) similar B) diminishing C) liability D) migrating

　　E) mutual F) mechanism G) effectively H) jerking

　　I) instantaneously J) vulnerable K) content L) baking

　　M) inherent N) perspective O) option

　　解题思路

　　1.[O]空格在指示代词that之后，应为名词。that所指与上一句内容有关，指“去沙滩之前先涂上防晒霜”。此处应选择option,表示海洋动物“没有那样的选择”。mechanism通常用于指事物本身内在的机制，不适宜用于指代“涂防晒霜”，故排除。

　　2.[L]空格所在句子主谓宾结构完整，且空格位于逗号后面，故应为分词作状语，说明鲸鱼在海面逗留六小时的状况。结合上文提到的关于“防晒”的内容，可以推断此处应该说鲸鱼每天“暴晒”六小时，故选baking最合适。

　　3.[F]虽然空格前的defense是名词，但从句宾语部分意思仍未完整，因此空格应该还是名词，被defense修饰作句子宾语。此处应选mechanism，表明鲸鱼自身拥有防晒的“保护机制”。

　　4.[D]空格前的before是介词，而空格后紧跟表方位的back to...，可见此处应该选用动词的现在分词，表明鲸鱼在度过了夏天之后的“动向”。动词库中的migrating—词最为恰当，填入文中表示“迁徙到北方去觅食”。

　　5.[G]空格在主语和谓语之间，故应为副词。本句提到抹香鲸体内的蛋白质可以保护它们不受紫外线的侵害。effectively符合句意，表明这种蛋白质的保护作用很“有效'

　　6.[A]根据空格后面的内容“人体如何产生抗氧化剂以应对造成大量遗传细胞损伤的分子”可知，本句类比了抹香鲸和人类自身的防护机制，故填人空格的词应含“类似”的意思，similar符合句意。

　　7.[K]空格在less和介词of之间，应为名词。本段主要讲皮肤黑色素(melanin)含量的多少决定mtDNA受损的程度。填入空格的词应与amount近义，content“含量”符合句意。

　　8.[B]空格在be动词和副词gradually之后，推断此处应为分词或形容词，说明现在臭氧层(ozone layer)所处的状态。通常指负面影响的consequences提示填入空格的词应为贬义词，因此选用diminishing， 表明臭氧层正在逐渐变小，保护地球免受紫外线辐射的作用也在减小。

　　9.[J] or提示填入空格的词可能是形容词或分词，与endangered并列;也可能是名词，与species并列。词库中的名词放入句中，句意不通。形容词vulnerable符合句意，表示逐渐减小的臭氧层对“脆弱的”物种会产生特别严重的影响。

　　10.[M]空格在名词之前，应为名词、形容词或分词作定语。由上文可知，鲸鱼体内有类似防晒霜的保护机制，因此 鲸鱼抗紫外线辐射的能力是自身就有的，故此处用inherent最合适。