Question

Nature is full of color, from rainbows and roses to butterfly wings and peacock tails. Even the fruits and vegetables you eat have different colors: blue blueberries, red strawberries, green broccoli, and orange carrots.

Plant and animals often use color to attract attention. The substances responsible for these colors belong to a class of chemical called antioxidants(抗氧化物). Plants make antioxidant to protect themselves from the sun’s ultraviolet(UV)(紫外線)light.

Ultraviolet light causes chemicals called free radicals(自由基)to form within plant cells. They can destroy parts of plant. Free radicals also have damaging effects on human beings. Some of these effects like wrinkled skin can be seen. The damage is caused by the free radicals attacking cells in our bodies. Certain cancers and heart disease are linked to free radicals.

Our bodies have natural defences for fighting off free radicals. While we are young, our defences are pretty strong. However, they get weaker as we get older. The body’s built-in defences can only go so far without extra help.

The key to fighting free radicals with fruits and vegetables is to mix and match colors. It’s like sunscreen(防曬霜)for the inside of your body. Go for a range of very bright colors. Colorful foods contain hundreds of healthy chemicals not found anywhere else.

Research into how chemicals in blueberries affect the brain’s function in rats suggests that these chemicals may help our own brains work more efficiently.

Don’t just blame the sun. Ultraviolet light isn’t the only source of free radicals. If you breathe polluted air such as smog, automobile exhaust(廢氣), or wasted gas from a factory, you take in chemicals that also cause such damage. And, the body itself produces free radicals as it processes food.

1.Which of the following not true?

A．Antioxidants are responsible for plant colors

B．Plants use color to attract attention

C．Antioxidants can protect plants from UV light

D．Antioxidants help free radicals to attack plants

2.In which order do the following facts occur?

a Wrinkled skin can be seen

b UV light causes free radicals to form

c Free radicals damage cells in our bodies

d The sun gives out UV light

A．a(chǎn),b,c,d                                B．d,b,c,a

C．c,a,d,b                                D．d,b,a,c

3.We need extra help for fighting off free radicals from fruits and vegetables because ____.

A．our bodies’ defences are not natural

B．we are too young to defend ourselves

C．our defences get weaker as we get older

D．our bodies’ built-in defences can only go away

4.Which of the following can not cause free radicals to form?

A．Colorful food                          B．UV light from the sun

C．Polluted air                            D．The body itself

 

Answer 1

【答案】

1.D

2.B

3.C

4.A

【解析】

試題分析：這篇文章講述了太陽(yáng)的紫外線、煙霧、汽車的排氣、工廠的廢氣等都可造成自由基的生成，自由基會(huì)破壞人體細(xì)胞，各種顏色的食物是幫助我們抗自由基的有效方法。

1.根據(jù)Plant and animals often use color to attract attention. The substances responsible for these colors belong to a class of chemical called antioxidants(抗氧化物). Plants make antioxidant to protect themselves from the sun’s ultraviolet(UV)(紫外線)light.排除A、B和C，故選D。

2.事情發(fā)生的先后順序是：先是太陽(yáng)釋放出紫外線，然后紫外線造成自由基的生成，接著自由基破壞我們身體的細(xì)胞，最后皮膚起皺紋，故選B。

3.根據(jù)However, they get weaker as we get older. The body’s built-in defences can only go so far without extra help.所以答案為C。

4.各種顏色的食物是幫助我們抗自由基的，因此選A。

考點(diǎn)：教育類短文閱讀理解

點(diǎn)評(píng)：要想答好題目，重在理解全文意思。這篇文章比較難，先看問(wèn)題，再帶著問(wèn)題讀短文，找出各段落的主旨句，理解全文內(nèi)容，總結(jié)全文中心，然后再回到問(wèn)題上來(lái)，很容易選出正確答案。