Question

【题目】

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（细胞）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（破骨细胞）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（成骨细胞）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（危机）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，讲述我们的身体由外到内，所有的细胞都在不断的新陈代谢，就连我们看似不变的身体的骨架，也在破骨细胞和造骨细胞的作用下，不断地更新。

【1】细节理解题。根据第二段Do you know how your fingernails and hair are constantly growing and replacing themselves? The same thing happens almost everywhere in your body.可知我们身体的每一个地方都在更新，A是错误；根据第二段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.可知身体的表皮、血管里的血细胞都在新陈代谢；所以B是正确的。根据第二段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，有的骨头长得快有的长得慢，实际上多数的骨细胞可以活50年，推断C错误。故选B。

【2】词义猜测题。根据第四段Bones have special cells called osteoclasts（破骨细胞）whose job is to break down bone, even if it isn't broken, and send the minerals into the blood stream.破骨细胞不断的损坏骨头，这听起来好像我们的骨头不断在受到磨损，即将“消亡”，故选C。

【3】主旨归纳题。本篇主要谈论我们的骨架看似不变，其实在破骨细胞和造骨细胞不断地作用下一直在更新，故选A。

本篇是阅读单选，考查细节理解、词义猜测、主旨大意和推理判断能力。解答前要先快速阅读全文，理解大意；在阅读题干，正确理解题干的要求；然后回归原文，寻找有用信息作答；本篇题型设定多样 ，有细节理解题、词义猜测题、主旨大意题和推理判断题，解答时需关注题干关键词，根据关键词寻找匹配答案；题1要仔细比对题干的每一个选项和信息句，排除干扰项；题2词义猜测根据上文的句意做出推断；题3要理解全文，避免做片面的判断。