Question

【題目】

You're not the same person you were as a child. You're not even the same personyou were five years ago. We don't just mean your personality. While we'd love tostart a never-ending discussion over the “true self”，we're here to talk about thecells（細(xì)胞）in your body.

Do you know how your fingernails and hair are constantly growing and replacingthemselves? The same thing happens almost everywhere in your body. Your outerlayer of skin makes way for fresher skin, and inside your veins（血管），blood cells turn over to make wayfor fresh blood. It's probably no surprise that these types of cells are short-lived, even some of the mostseemingly permanent（永久的）parts of your body replace themselves over time-including your bones.

Strong as your bones might seem, the cells they're made of won't last a lifetime. Bones are masters at rebuilding themselves, which is why most broken bones can heal on their own into the right shape.

Bones have special cells called osteoclasts（破骨細(xì)胞）whose job is to break down bone, even if itisn't broken, and send the minerals into the blood stream. This may sound frighteningly like your bonesare wearing away, but your body knows what it's doing. As osteoclasts break down bone, osteoblasts（成骨細(xì)胞）build up new bone to replace the old. By the end of each year, about 10 percent of yourentire adult skeleton will have been rebuilt through this process.

If 10 percent of your bone breaks down every year, it must take about ten years to renew 100percent of your skeleton. That would be a great guess, and it lines up nicely with the medical myth thatthe human body's cells are fully replaced every seven years, but the body is a bit more complex. That10 percent is just an average-some bone grows faster than that, and some grows slower. While someparts of your bone will turn over quickly, other parts will stick around for decades. In fact, most bonecells could live as long as 50 years.

So before you get wrapped up in an identity crisis（危機(jī)）about the cells in your body disappearingon you, know that you can lose some hair and you can cut your nails, but the bones of you aren't goinganywhere-at least not very soon and not all at once.

【1】Which of the following is TRUE according to the passage?

A. All the cells in our body are the same ones that we were born with.

B. Our blood cells are constantly growing and replacing themselves.

C. It must take about 10 years to rebuild 100 percent of our skeleton.

D. Osteoblasts can break down skin and also rebuild it over time.

【2】The underlined words "wearing away" probably mean“＿＿”．

A. building upB. taking offC. dying outD. turning on

【3】What does the passage mainly talk about?

A. Our skeleton seems permanent but renews itself over time.

B. It is not surprising that some cells in our body are short-lived.

C. There are two types of cells in our bones: osteoclasts and osteoblasts.

D. We are not the same person we were five years ago because of personality.

Answer 1

【答案】

【1】B

【2】C

【3】A

【解析】

本篇是科普文章，講述我們的身體由外到內(nèi)，所有的細(xì)胞都在不斷的新陳代謝，就連我們看似不變的身體的骨架，也在破骨細(xì)胞和造骨細(xì)胞的作用下，不斷地更新。

【1】細(xì)節(jié)理解題。根據(jù)第二段Do you know how your fingernails and hair are constantly growing and replacing themselves? The same thing happens almost everywhere in your body.可知我們身體的每一個地方都在更新，A是錯誤；根據(jù)第二段Your outer layer of skin makes way for fresher skin, and inside your veins（血管），blood cells turn over to make way for fresh blood.可知身體的表皮、血管里的血細(xì)胞都在新陳代謝；所以B是正確的。根據(jù)第二段That10 percent is just an average-some bone grows faster than that, and some grows slower. While some parts of your bone will turn over quickly, other parts will stick around for decades. In fact, most bone cells could live as long as 50 years.可知10年只是平均值，有的骨頭長得快有的長得慢，實際上多數(shù)的骨細(xì)胞可以活50年，推斷C錯誤。故選B。

【2】詞義猜測題。根據(jù)第四段Bones have special cells called osteoclasts（破骨細(xì)胞）whose job is to break down bone, even if it isn't broken, and send the minerals into the blood stream.破骨細(xì)胞不斷的損壞骨頭，這聽起來好像我們的骨頭不斷在受到磨損，即將“消亡”，故選C。

【3】主旨?xì)w納題。本篇主要談?wù)撐覀兊墓羌芸此撇蛔�，其實在破骨�?xì)胞和造骨細(xì)胞不斷地作用下一直在更新，故選A。

本篇是閱讀單選，考查細(xì)節(jié)理解、詞義猜測、主旨大意和推理判斷能力。解答前要先快速閱讀全文，理解大意；在閱讀題干，正確理解題干的要求；然后回歸原文，尋找有用信息作答；本篇題型設(shè)定多樣 ，有細(xì)節(jié)理解題、詞義猜測題、主旨大意題和推理判斷題，解答時需關(guān)注題干關(guān)鍵詞，根據(jù)關(guān)鍵詞尋找匹配答案；題1要仔細(xì)比對題干的每一個選項和信息句，排除干擾項；題2詞義猜測根據(jù)上文的句意做出推斷；題3要理解全文，避免做片面的判斷。