GRE閱讀｜ For some time scientists have believed that cholesterol plays a major role in heart disease because people with familial hypercholesterolemia－熱血背包客莊ㄟ

For some time scientists have believed that cholesterol plays a major role in heart disease because people with familial hypercholesterolemia, a genetic defect, have six to eight times the normal level of cholesterol in their blood and they invariably develop heart disease. These people lack cell-surface receptors for low-density lipoproteins (LDL‘s), which are the fundamental carriers of blood cholesterol to the body cells that use cholesterol. Without an adequate number of cell-surface receptors to remove LDL‘s from the blood, the cholesterol-carrying LDL‘s remain in the blood, increasing blood cholesterol levels. Scientists also noticed that people with familial hypercholesterolemia appear to produce more LDL‘s than normal individuals. How, scientists wondered, could a genetic mutation that causes a slow-down in the removal of LDL‘s from the blood also result in an increase in the synthesis of this cholesterol-carrying protein?

Since scientists could not experiment on human body tissue, their knowledge of familial hyper- cholesterolemia was severely limited. However, a breakthrough came in the laboratories of Yoshio Watanabe of Kobe University in Japan in 1980. Watanabe noticed that a male rabbit in his colony had ten times the normal concentration of cholesterol in its blood. By appropriate breeding, Watanabe obtained a strain of rabbits that had very high cholesterol levels. These rabbits spontaneously developed heart disease. To his surprise, Watanabe further found that the rabbits, like humans with familial hypercholesterolemia, lacked LDL receptors. Thus, scientists could study these Watanabe rabbits to gain a better understanding of familial hyper- cholesterolemia in humans.

1. In the passage, the author is primarily concerned with

(A) presenting a hypothesis and describing compelling evidence in support of it

(B) raising a question and describing an important discovery that led to an answer

(D) explaining what causes the genetic mutation that leads to heart disease

(E) discussing the importance of research on animals for the study of human disease

For the following question, consider each of the choices separately and select all that apply

2. The passage supplies information to answer which of the following questions EXCEPT?

(A) Which body cells are the primary users of cholesterol?

(B) How did scientists discover that LDL‘s are secreted from the liver in the form of a precursor?

3. The passage implies that if the Watanabe rabbits had had as many LDL receptors on their livers as do normal rabbits, the Watanabe rabbits would have been

(A) less likely than normal rabbits to develop heart disease

(B) less likely than normal rabbits to develop high concentrations of cholesterol in their blood

(D) unable to secrete VLDL‘s from their livers

(E) immune to drugs that lower cholesterol levels in people with certain forms of familial hypercholesterolemia

4. The passage implies that Watanabe rabbits differ from normal rabbits in which of the following ways?

(A) Watanabe rabbits have more LDL receptors than do normal rabbits.

(B) The blood of Watanabe rabbits contains more VLDL remnants than does the blood of normal rabbits.

(D) Watanabe rabbits secrete lower levels of VLDL‘s than do normal rabbits.

(E) The blood of Watanabe rabbits contains fewer LDL‘s than does the blood of normal rabbits.

結構分析：

For some time scientists have believed that cholesterol plays a major role in heart disease because people with familial hypercholesterolemia, a genetic defect, have six to eight times the normal level of cholesterol in their blood and they invariably develop heart disease. These people lack cell-surface receptors for low-density lipoproteins (LDL‘s), which are the fundamental carriers of blood cholesterol to the body cells that use cholesterol（照慣例代名詞出現一律先省略）. Without an adequate number of cell-surface receptors to remove LDL‘s from the blood, the cholesterol-carrying LDL‘s remain in the blood, increasing blood cholesterol levels.（而這句不看原因是因為他在對上面一句做補充，看到without就可以表示他在下條件，我們把某種條件限定出來，表示這層邏輯是在概念下面的一種舉例，並做一個假設性動作，假如我之前所說的概念不存在會發生什麼事情，所以上下兩句形成互補，一正一負） Scientists also noticed that people with familial hypercholesterolemia appear to produce more LDL‘s than normal individuals. How, scientists wondered, could a genetic mutation that causes a slow-down in the removal of LDL‘s from the blood also result in an increase in the synthesis of this cholesterol-carrying protein?

首先看到第一句藉由科學家觀點引出主題，科學家贊成：Ｃ就是心臟病的兇手，那接下來的結構可能就會是另外一派認為『Ｃ不是心臟病的兇手』兩者對立的文章，或者是一路支持到底這兩種可能，不過這都只是在『猜測』，因為一般文章出現立場主張，通常都是這樣發展的，當然也可以不用想那麼多繼續看，只不過還是會稍微猜測一下，以免到時候受到驚嚇，那抱著這樣的想法再往下看，後頭馬上給出支持解釋了，because 因果關係出來我通常是不看的只要記得開頭『Ｃ就是心臟病的兇手』有題出支持解釋即可，但是這裡比較要注意的兩個事情是six to eight times and they invariably develop heart disease，這兩個事情在告訴讀者，這不是猜測，是有實驗依據的，一個是給出了具體數據，第二個是副詞invariably＝100%。

接下來直接跳到Scientists also noticed....這裡也是只要注意到那個並列邏輯詞即可，並別表示邏輯同向也是在說『Ｃ就是心臟病的兇手』，至於後面喵一下看到produce more LDL‘s 有個比較關係，這也是喵喵就好，我是覺得不重要拉，這抓結構沒必要細看，只要把主題跟結果（結論）抓住即可，中間的原因解釋啊，這都是細節了，有考到在看。所以我們對這句也不需停留太久，目光直接進入到最後一句話，

How, scientists wondered, could a genetic mutation that causes a slow-down in the removal of LDL‘s from the blood also result in an increase in the synthesis of this cholesterol-carrying protein?

這個重點來了，疑問句通常是必看的，而且他在結尾段，並結由一個表結論關係的因果詞 result in 引導，再來看到內容是問how，這表示我剛剛猜測錯誤了，本以為是立場的支持與反駁文章，沒想到直接把正負立場的打架過程給跳過，直接來到，對沒錯，科學家承認Ｃ就是心臟病的兇手，那你怎麼知道的？？這裡馬上把立場對立型式的轉折文的可能性剔除，所以接下來一定是一個『大順子』文章，一路邏輯同向到底，除非中間有轉著字眼出現，好拉～～所以總結第一段給我的訊息是：Ｃ就是心臟病的兇手，血液特濃Ｘ6，一定變心臟病，較多的LDL's

By appropriate breeding, Watanabe obtained a strain of rabbits that had very high cholesterol levels. （還是在講ＹＷ教授怎麼了，所以還是細節，我一樣忽略）These rabbits spontaneously developed heart disease（代名詞出現了就別看）. To his surprise, Watanabe further found that the rabbits, like humans with familial hypercholesterolemia, lacked LDL receptors.（原因除了有代名詞the rabbits之外，最重要的其實是To his surprise這種表原因的句式都是在做邏輯同向的解釋跟補充說明而已，不值得一看，因為邏輯都是Ｃ就是心臟病的兇手） Thus, scientists could study these Watanabe rabbits to gain a better understanding of familial hyper- cholesterolemia in humans.（這裡給出結論，又看到代名詞these Watanabe rabbits，下場就是砍掉不重練）

先刪選過我認為該看的內容之後，要來講他們必須看的理由，第二段開始囉～～首先說到沒有實驗，因為受到限制啊，這時候不用擔心，因為後方的轉折詞出現，表示這個實驗還是有機會完成的，接著我對後面稍微記一下是怎樣的實驗即可，前方的就不理他了，都已經被打槍了他的存在已經沒有意義，第二句後方只有留下人名Yoshio Watanabe，那我筆記為ＹＷ，立馬往下看，看到開頭是Watanabe這位教授，那以下自動忽略，因為頂多就是補充ＹＷ做啥事情，我期待的邏輯還是跟第一段一樣：Ｃ就是心臟病的兇手

Prior to the breakthrough at Kobe University, it was known that LDL‘s are secreted from the liver in the form of a precursor, called very low-density lipoproteins (VLDL‘s), which carry triglycerides as well as relatively small amounts of cholesterol.（同位語跟關係代名詞的修飾詞，不是主幹） The triglycerides are removed from the VLDL‘s by fatty and other tissues.（代名詞出現，而且這個字triglycerides見都沒見過，表示他是細節） What remains is a remnant particle that must be removed from the blood.（the blood細節裡的東西，這句話連主角Ｃ都沒有，這直接跳了） What scientists learned by studying the Watanabe rabbits is that the removal of the VLDL remnant requires the LDL receptor.（這個也是代名詞太多了，刪掉） Normally, the majority of the VLDL remnants go to the liver where they bind to LDL receptors and are degraded.（看到normally表示在限定條件了，那這也是舉例，被我歸類成細節支持概念用的） In the Watanabe rabbit, due to（表原因不看） a lack of LDL receptors on liver cells, the VLDL remnants remain in the blood and are eventually converted to LDL‘s. The LDL receptors （代名詞）thus （就算他有結論行副詞我照樣跳過，因為我沒看到主角Ｃ啊）have a dual effect in controlling LDL levels. They（代名詞跳） are necessary to prevent oversynthesis of LDL‘s from VLDL remnants and they are necessary for the normal removal of LDL‘s from the blood. With this knowledge（又來代名詞）, scientists are now well on the way toward developing drugs that dramatically lower cholesterol levels in people afflicted with certain forms of familial hypercholesterolemia.（全都別看啦～～）

我看到第一句的Prior to趕快看一下是否有新舊對比，結果我看到的是 it was known that LDL‘s這老兄早就已經知道了，靠腰這只是背景交代句，好拉我的期待落空，邏輯上還是延續上一段，這裡繼續往那ＹＷ兔子的細節走。然後隨著文章的廢話來到了最後一行, scientists are now well on the way toward developing drugs that dramatically lower cholesterol levels in people afflicted with certain forms of familial hypercholesterolemia.因為prior to VS. now 有個新舊對比，不管他們比的東西是否相同，就概念上他們具有時間對立的關係存在，還是必須在考試時注意，原來是要說科學家發現『有辦法生藥出來了』到這裡考試時應該先抓的結構就有了，總共會看到七句話，分配上大概就是每段兩句左右，所以長文章其實也可以取頭尾看拉～如果沒有想法要看哪裡的時候就取頭尾吧，因為尾句具有承上啟下的功用，而首句具有點出主題的作用。

來畫個圖之後就來秒殺題目囉～～

1. In the passage, the author is primarily concerned with

(A) presenting a hypothesis and describing compelling evidence in support of it

(B) raising a question and describing an important discovery that led to an answer

(D) explaining what causes the genetic mutation that leads to heart disease

(E) discussing the importance of research on animals for the study of human disease

解題：

關鍵在那個第一段最後一句的疑問句，再來ＹＷ的實驗是具體存在的事實，所以選（Ｂ）

補充：

（Ａ）錯在hypothesis＋compelling evidence，感覺好像OK，不過這樣只能表達第一段第一句話，並且這樣會變成立場辯論型文章，就是誰對誰錯，那個HOW是連接文章的關鍵，使得原本可能是立場支持或對立辯論文，也就是誰對誰錯已經決定好了，變成很普通的解釋說明文

（Ｃ）更扯，完全不把HOW當一回事，a certain genetically caused disease＝Ｃ，be treated effectively with drugs＝well on the way toward developing drugs這根本把文章去頭去尾了，老兄這不是在吃魚啊

（Ｄ）不是『什麼』，而是『如何』。

（Ｅ）文章的ＹＷ研究是來支持Ｃ就是心臟病的兇手，所以它的作用在於解釋支持主題，跟importance他自己重不重要無關。

2. The passage supplies information to answer which of the following questions EXCEPT?

(A) Which body cells are the primary users of cholesterol?

(B) How did scientists discover that LDL‘s are secreted from the liver in the form of a precursor?

解題：

（Ａ）對應原文是 These people lack cell-surface receptors for low-density lipoproteins (LDL‘s), which are the fundamental carriers of blood cholesterol to the body cells that use cholesterol.

這裡提到的是一個機制，把Ｃ藉由血液講之傳到需要Ｃ的細胞，因此重點不在問哪一個細胞

（Ｂ）LDL's很早就發現了，第三段第一句話有讀到

（Ｃ） Normally, the majority of the VLDL remnants go to the liver where they bind to LDL receptors and are degraded. 就在肝臟中，所以有解釋道where

這題最麻煩了完全考在細節裡，選（Ａ）（Ｂ）

3. The passage implies that if the Watanabe rabbits had had as many LDL receptors on their livers as do normal rabbits, the Watanabe rabbits would have been

(A) less likely than normal rabbits to develop heart disease

(B) less likely than normal rabbits to develop high concentrations of cholesterol in their blood

(D) unable to secrete VLDL‘s from their livers

(E) immune to drugs that lower cholesterol levels in people with certain forms of familial hypercholesterolemia

解釋：

看到implies就想到推理題，題目條件給到的事the Watanabe rabbits had had as many LDL receptors on their livers as do normal rabbits表示他的同屬性比較對象應該在文章中是含有不一樣的LDL receptors所以對應到內容To his surprise, Watanabe further found that the rabbits, like humans with familial hypercholesterolemia, lacked LDL receptors.

找出對比對象後，於是進入對比推理法程序，Watanabe rabbits had LDL receptors （題目）VS. the rabbits lacked LDL receptors.（文章內容）很明顯知道邏輯上『兩者相反』，接著看到the rabbits lacked LDL receptors.帶出的內容是 like humans with familial hypercholesterolemia，如果要選出答案就對她取『反向』邏輯即可，也就是 unlike humans with familial hypercholesterolemia，選（Ｃ）

4. The passage implies that Watanabe rabbits differ from normal rabbits in which of the following ways?

(A) Watanabe rabbits have more LDL receptors than do normal rabbits.

(B) The blood of Watanabe rabbits contains more VLDL remnants than does the blood of normal rabbits.

(D) Watanabe rabbits secrete lower levels of VLDL‘s than do normal rabbits.

(E) The blood of Watanabe rabbits contains fewer LDL‘s than does the blood of normal rabbits.

解題：

又來一題推裡題，題目問不同，那麼我的預想是他既然要找不同之處，本文主角是在討論Ｃ，既然如此Ｃ一定異於常人才有討論價值，所以搜尋對象應該專注在Watanabe rabbits上，因此我的範圍可以縮小到二三段了，就著將提到Ｗ小兔的內容都過一便，如下

These rabbits spontaneously developed heart disease.

To his surprise, Watanabe further found that the rabbits, like humans with familial hypercholesterolemia, lacked LDL receptors.

Thus, scientists could study these Watanabe rabbits to gain a better understanding of familial hyper- cholesterolemia in humans.

像上面綠色部分一看就知道差別的這根本不用推理，所以他們都不會是目標句，既然題目表明implies了，那答案當然是要旁敲側擊才會出來，這種赤裸裸就知道答案的只會是細節題的考法。

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What scientists learned by studying the Watanabe rabbits is that the removal of the VLDL remnant requires the LDL receptor.

In the Watanabe rabbit, due to a lack of LDL receptors on liver cells, the VLDL remnants remain in the blood and are eventually converted to LDL‘s.

這兩句關鍵來了，要用拐彎抹角的方式呈現才是推理題精髓，這裡對比點就是Ｗ小兔（缺LDL receptors ） VS. 一般兔（LDL receptors正常），然後座標原點：LDL receptors，接著內容就告訴你the removal of the VLDL remnant requires the LDL receptor.移除VLDL要用到，所以現在條件有了，兩個對比對象是邏輯相反的，所以內容上因為缺LDL receptors，會導致the VLDL remnant一直在血中，所以血中當然就是比較多的 VLDL remnant，此時再回看選項，只要內容有VLDL remnant或是LDL receptor先留著，其他謝謝再聯絡，如此一來只會留下（Ａ），（Ｂ）接著再用你的膝蓋選出答案就完成了，選（Ｂ）

以上筆記供大夥參考若有錯誤再煩請指教