false_False or Not Given （对，错，文中未提及）

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mcq题要求考生在abcd四个选项中选择一个正确答案，其他三个选项同原文提供的信息相反或不符。如原文可能说生物课在r201室上课，而mcq的一个选项是r202。显然，这个选项不是正确答案，不能选。
做选择题主要可以采用如下几种方法：1、如果问题中的内容在文章中有明确阐述，根据文章内容判断并选择正确的答案；2、如果问题中的选项在文章中没有直接表述，则需要根据文章中的内容进行推断，然后得出结论并选择正确答案；3、如果没有办法根据文章中的内容确定正确答案，则可以从选项中把错误答案逐个排除，剩下的就是正确答案了。
做选择题时可以应用一些小窍门，比如，要先看文章后面的题目，然后带着问题从文章中找答案。简单的办法就是通过skimming 与scanning在文中找出与问题相对应的词语或句子，在下面划线，然后再从这些地方去寻找答案。
此外，在英语文章中，尤其是学术类的文章中，很少出现非常绝对的提法，因此文章中也就极少会用到象absolutely, definitely 等表示‘彻底、绝对肯定或否定’的词语。所以，如果选项中出现这样的词，基本上就不用考虑它所在的句子了。
下面，让我们用sample exercise为例子，来具体分析一下做选择题的方法。

sample exercise
shark senses
the shark"s sixth sense: the shark has all the senses that we humans do but they also have one we don"t have. tiny pores on the snout leads to jelly-filled sacs known as ampullae’s of lorenzini. this sense can detect very weak electrical fields that can detect electrical "vibes" as weak as half a billionth of a volt. struggling or scared animal creates a strong electrical current, which flows through the water, and even though it gets weaker as it travels away from the animal, sharks can pick it up. every animal sends electrical "vibes". a shark can find animals under the sand, and at night, and when at the last moment of attack when the eyes are rolled back and it cannot see. in many cases when doing shark research the shark would attack the boat and other objects instead of the food offered. humans used to think that the shark was just a stupid, crazy eating machine that went after anything. it turns out however that the shark when coming for the prey would roll it"s eyes back and have the ampullae’s of loranzini direct it to the prey. the boat gives out very strong electrical "vibes" which confuse the shark and direct it to the boats direction, and since the shark cannot see at the moment it would not know the boat is not the prey. hammerhead sharks have a large number of ampullae’s of lorenzini on their heads. hammerheads use their heads like mine sweepers to find stingrays, and other prey in the sand. large number of hammerheads can be found near underwater volcanoes which attract them from miles away with their electrical fields. the rare and strange goblin shark has a strange snout hanging over is head which may be used the same way as a hammerheads head and help it hunt in the deep dark water it lives in. goblin shark teeth have been found in underwater electrical cables.
the lateral line: the lateral line is another sense that we human do not have. the lateral line is a fluid filled canal that is lined with tiny hair like receptors that are attuned to vibrations made by prey. these lateral lines are located just under the skin on the shark"s snout and along both sides of the body. these lines are also in bony fish. fish (sharks included) can also use these lines to sense water currents and pressures and even sounds. some say that the bumping behavior of sharks allows external taste receptors to see if the organism is edible (this may explain why sharks often bump objects).
smell: unlike the nostrils of "higher" animals, sharks are not used for respiratory functions. the shark can sense one molecule of blood in a million molecules of water. each nostril is divided by a skin flap, which separates the water flowing in and out. as the fish swims, water enters the nostrils and through the nasal capsule that contains lamellae. lamellae increase the shark"s sensitivity to odors. the olfactory bulb is close to the front of the brain.
hearing: the shark has an excellent sense of hearing and can hear the low pulsing sounds made by animals swimming, splashing, and struggling. these sounds are too low for humans to hear, however sharks can hear them from a thousand miles away. sharks do not have external ear flaps, but instead have ears inside their heads on both sides of the brain case. each ear leads to a small pore on the sharks head. a shark"s inner ear can also detect acceleration, and gravity.
sight: it was once thought that sharks had very bad eyesight, and were nearly blind. it is now known that sharks have very good eyesight, some better than ours. like cats, a shark"s eye contracts or expands to alter the size of the pupil, according to how much light there is. in the back of the eye there is a layer of cells known as the tapetum lucidum. the cells reflect light back onto the retina. this is where images are focused, making good use of light. due to this a sharks can see in dim light, and the eye "glows" like a cat when light is shined on them. with pigment layers a shark can protect it"s eyes on sunny days. the shark"s eyes also have cells called rods, and cones. the rods work in dim light and are sensitive to changes in light. the cones may allow sharks to see color. we humans have rods, and cones. fish lack eyelids because they don"t need to blink and clean their eyes due to their watery environment. during attack some sharks use their nictitating membranes (translucent eyelids) to protect them from the thrashing animal. sharks that have no nictitating membranes, like the great white for example roll their eyes into the back to their heads. the size, shape, and overall look of a shark"s eye depends on their environment. deepwater sharks have large eyes to take in more light, while smaller eyes are on sharks that live closer to the surface. it was once thought that great white attacks on surface were cases of mistaken identity, but researchers now know that this theory is not likely for a few reasons. reason one is because white sharks have excellent vision and can probably tell the difference between a human on a surfboard, and a seal. the second reason is this; when a white shark attacks a seal it makes one huge bite, and kills the seal on the spot. when humans are attacked the shark usually takes one small bite and swims off. if the shark thought we were seals then it would do to us what it doses to the seals.

choose the appropriate letters a-d and write them on your answer sheet.

1. which senses are the ones that sharks have, but humans have not?

a. the sixth sense
b. ampullae’s of lorenzini
c. lateral line
d. b and c

2. according to the author, sharks...

a. are stupid, crazy eating machines
b. go after everything
c. have very bad eyesight
d. are confused by the electrical vibes sent out by the boat    

3. why are many hammerheads found gather around underwater volcanoes?

a. because they have a large number of ampullae’s of lorenzini
b. because the water there is warm
c. because they are attracted by the electrical fields there
d. because they can find prey in the volcanoes’ sand     

4. the lateral line...

a. helps sharks to detect the movement of a quarry
b. helps sharks to detect electrical fields
c. helps sharks to sense water speed
d. all of the above     

5. the nostrils of the shark are for...

a. breathing air
b. perceiving scents
c. separating water
d. steering        

6. images are focused on...

a. the tapetum lucidum
b. ampullae’s of lorenzini
c. retina
d. none of the above      

7. according to the writer, the great white attacks human beings, because...

a. it confuses a human being with a seal
b. it has excellent eyesight
c. it has poor eyesight
d. not given     

从文章的标题我们可以知道这是一篇关于鲨鱼感觉（shark senses）的文章。每段文章的开头都用了大写字母，清楚地告诉我们文章的各个段落分别是the shark’s sixth sense， the lateral line， smell， hearing， sight。
让我们来看问题1: which senses are the ones that sharks have, but humans have not?
第一段的标题是the shark’s sixth sense。大家都知道，人有听觉、视觉、嗅觉、触觉、味觉五种感觉，而第六感觉一般是指心灵感应等尚待证明的感知功能。因此，通过快速判断，考生可以猜测到本段描写的是鲨鱼所特有的感觉。接下去看头两句，果不其然，第一句讲的是鲨鱼拥有我们人类所有的感觉，但还有其特有的感觉。第二句讲的是在它的嘴上有一些小孔，连到一些叫做ampullae’s of lorenzini的sacs上。一下子我们就遇到了三个生词。怎么办？不要紧，通过意群分析法，jelly-filled sacs的名字叫作ampullae’s of lorenzini，因此只要集中注意力在ampullae’s of lorenzini上就可以了，不用管sacs是什么意思。但应当选a还是b呢？通过判断可以得知，a只是笼统的一个标题，并没有说清这种感觉到底是什么。而b则明确地写出了名称。但选b就可以了吗？如果不仔细看题，或因时间原因，匆匆选择，就落入了出题者设下的陷阱。在mcq题型中，通常会有一些all of the above, none of the above, a and b, a or b等选项。对这类选项一定不能掉以轻心，必须认真比较，考虑出题者为什么会在仅有的四个选项中出这么一个题？以本题为例，第四选项是b and c，即c也是鲨鱼所特有的感觉。跳到the lateral line一段阅读，果然，lateral line is another sense that …因此做mcq题一定不能想当然，每个选项都必须看到，进行比较，这样才不至于马虎，把该拿到手的分数白白丢掉。

问题2: according to the author, sharks....。这个问题很明显是在对全文的总体感觉提问,也就是说，作为读者，读完全文后，你感觉作者的态度是什么。一般说来，这种全局性问题的答案总是在第一段或最后一段中。果然，我们在第一段中找到了这样的一段话：human used to think that the shark was just a stupid, crazy eating machine that went after anything. it turns out however that the shark when coming for the prey would roll its eyes back and have the ampullae’s of loranzini direct it to the prey. the boat gives out very strong electrical "vibes" which confuse the shark and direct it to the boats direction....

从这段话我们可以找到第二题的答案。可以肯定，前两个选项都不对，因为这是人们以前对鲨鱼的误解，作者并没有这么认为。used to, it turns out, however这些词都发出了强烈的信号，即大家所认为的sharks are stupid, crazy eating machine that go after anything是错误的。此外，作者发现，鲨鱼错把船只当作猎物的原因是它把船只发出的‘electrical vibes"与猎物们发出的‘electrical vibes"混淆了，而且，此时它只是没有用眼睛而并非是眼力太差的缘故。如果考生还不放心，可快速浏览sight一段，即可发现it was once thought that sharks had very bad eyesight…it is now known that sharks have very good eyesight。因此，我们可以肯定，正确答案是d。

问题3：why are many hammerheads found gather around underwater volcanoes?
看完这个问题，我们首先应当想到的是要到哪里去找答案？什么是hammerheads？既然文章是讲鲨鱼的，那hammerheads一定是一种鲨鱼，至少也是一种鱼的名字吧。对专有名词进行paraphrase比较少见，因此以hammerhead为target word对文章进行扫描，很快就可以在第一段找到好几个hammerheads。通过阅读了解到，鲨鱼是被电场吸引才聚集到水底火山附近的，而至于它们是否要到火山沙里去找猎物或因为那里的水温高就到那里去，文章并没有提及。选择这道题的答案时，应该根据文章内容直接选出，不需要用排除法。

问题4： the lateral line....
看到lateral line当然就要到以lateral line为标题的段落中去找答案了。在该段中我们看到，the lateral line is a fluid filled canal that is lined with tiny hair like receptors that are attuned to vibrations made by prey. … fish (sharks included) can also use these lines to sense water currents and pressures and even sounds。意思是鲨鱼的lateral line 可以感觉到猎物造成的振动、水流、压力甚至是声音。问题所给出的选项有：探测猎物的运动，探测磁场，感应水的流速。但文章只说能感觉水流，而不是流速，因此通过排除法，只剩下a和b。a在文中已有明确表述，如果大家因不认识quarry而对这个选项信心不足，也可以通过排除b来选a。因为通过阅读第一段已经知道，鲨鱼是通过ampullae’s of lorenzini来感知electrical field的。

问题5: the nostrils of the shark are for....
    从nostrils一词我们可以联想到nose，接着联想到smell。这样直接去smell一段中去找答案就省去了很多时间。当然，如果不知道nostril的意思，也可以通过扫描的方法在文中找到含有nostril的句子，但这就费时多了（而且，如果不认识nostril一词的话，真是该努力一下“我爱背单词”了：）。
从前两句话中我们可以了解到：鲨鱼的鼻孔不是用来呼吸的；，它们能够感觉到水中的血滴。这样，a首先就可以排除掉了。第三句中出现了separate water，但它是出现在由which引导的非限定性定语从句中，修饰的是skin flap，而不是nostril。因此c选项也可以排除。d选项steering在文中未出现过，只是用于迷惑考生，分散他们的注意力。此外，odor 和scent是同义词，只要能读懂这段的大意，b选项是可以准确地选中的。

问题6： images are focused on....
由于问题中提到的是image（图像）， 所以我们应该在sight 这一段中寻找答案。在该段中，我们发现了下面的句子：in the back of the eye there is a layer of cells known as the tapetum lucidum. the cells reflect light back onto the retina. this is where images are focused....
在问题后面给出的选项中，我们发现了tapetum lucidum，ampullae of lorenzini和retina。 ampullae of lorenzini在第一段出现过，主要是和电场有关，因此可以排除掉。tapetum lucidum 看起来有点象，可是仔细读读原文，this is where images are focused。 this在这里很重要，判断它指的是tapetum lucidum还是retina是本题的关键。通过语法分析，this指的是the subject of the most immediate sentence in the above context，所以retina应当是本题的答案。本题再一次说明了，在选项中经常有一些看似正确的答案，但是千万不能大意，一定要把所有的选项都看完，仔细区别后再做选择。

问题7：according to the author, the great white attacks human beings, because...
在文章最后一段的后半部分，我们发现与问题有关的句子：it was once thought that great white attacks on surface were cases of mistaken identity, but researchers now know that this theory is not likely for a few reasons...从中我们可以推断出下面的意思：以前人们认为大白鲨攻击人类是因为它认错了‘人’，但是，研究人员现在知道这个理论不太可能成立，并且列举了若干原因。可见，大白鲨攻击人类不是因为它眼神不好，分不清人和海豚，文章中列举出的原因只是在反驳它攻击人类是因为混淆了人和海豚的理论，但是并没有说明它为什么攻击人类。尽管文章中提到它具有很好的视觉，但是这一点与问题并没有什么关联。因此，我们可以排除掉abc三个选项，选择d。

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