The other day, I bought an expensive anti-aging cream that promised to make my face look several years younger that other women by fighting free radicals. It made me curious about what free radicals ares.Is the anti-aging cream the only way I need to protect myself?
“As a scientific term, free radicals are essentially unstable atoms, “says Arizona-based doctor, Natasha Bhuyan, M. D. “In medicine, they cause cells to break down over time and are linked to aging.”
A super simple chemistry review for you: Atoms from different elements are the building blocks that make up water, nitrogen and more. Electrons (电子) are the negatively charged atoms, and they like to be in pairs. When an electron loses its partner, it creates a free radical, which is usually unstable and highly reactive. Free radicals typically go through the body to seek out a replacement for their missing electron, and that can result in damage to cells,proteins and DNA.
So how do free radicals form and why do they happen? Bhuyan says, “Scientifically, free radicals are unpaired electrons that are seeking a mate to bond with. The theory behind free radicals is that they can lead to the imbalance between free radicals and antioxidants (抗氧化剂).” Another mini-science lesson for you: Antioxidants are natural or man made matters that can help delay or prevent some types of cell damage. They’re often found in fruits and vegetables.
A lot of the aspects of modern life — our diet, lifestyle and environmental factors like pollution, can cause oxidative stress. Over time, oxidative stress weakens cell and tissues and can leave you more easily to certain health issues including cancer. And, as beauty marketers are keenly aware,oxidative stress can also speed up the aging process. Now that your know free radicals can weak on your health, you’re probably wondering if there are any ways to prevent them from forming or at least to minimize their negative effects.
1.What does the author intend to do in paragraph 1?
A.Explain the process of aging. B.State the formation of free radicals.
C.Introduce the topic of free radicals. D.Describe the harm of anti aging cream.
2.Which of the following do free radicals refer to?
A.Unpaired electrons. B.Steady atoms.
C.Replacements of atoms. D.Functions of electrons.
3.What can we learn about antioxidants from the text?
A.They have never been found in nature.
B.They do harm to cells, proteins and DNA.
C.They can slow down the damage of some cells.
D.They always keep balance with free radical.
4.What will the author probably tell us next?
A.What exactly oxidative stress is. B.How beauty marketers promote sales.
C.Where a variety of diseases come from. D.Whether free radicals can be prevented.
高三英语阅读理解中等难度题
The other day, I bought an expensive anti-aging cream that promised to make my face look several years younger that other women by fighting free radicals. It made me curious about what free radicals ares.Is the anti-aging cream the only way I need to protect myself?
“As a scientific term, free radicals are essentially unstable atoms, “says Arizona-based doctor, Natasha Bhuyan, M. D. “In medicine, they cause cells to break down over time and are linked to aging.”
A super simple chemistry review for you: Atoms from different elements are the building blocks that make up water, nitrogen and more. Electrons (电子) are the negatively charged atoms, and they like to be in pairs. When an electron loses its partner, it creates a free radical, which is usually unstable and highly reactive. Free radicals typically go through the body to seek out a replacement for their missing electron, and that can result in damage to cells,proteins and DNA.
So how do free radicals form and why do they happen? Bhuyan says, “Scientifically, free radicals are unpaired electrons that are seeking a mate to bond with. The theory behind free radicals is that they can lead to the imbalance between free radicals and antioxidants (抗氧化剂).” Another mini-science lesson for you: Antioxidants are natural or man made matters that can help delay or prevent some types of cell damage. They’re often found in fruits and vegetables.
A lot of the aspects of modern life — our diet, lifestyle and environmental factors like pollution, can cause oxidative stress. Over time, oxidative stress weakens cell and tissues and can leave you more easily to certain health issues including cancer. And, as beauty marketers are keenly aware,oxidative stress can also speed up the aging process. Now that your know free radicals can weak on your health, you’re probably wondering if there are any ways to prevent them from forming or at least to minimize their negative effects.
1.What does the author intend to do in paragraph 1?
A.Explain the process of aging. B.State the formation of free radicals.
C.Introduce the topic of free radicals. D.Describe the harm of anti aging cream.
2.Which of the following do free radicals refer to?
A.Unpaired electrons. B.Steady atoms.
C.Replacements of atoms. D.Functions of electrons.
3.What can we learn about antioxidants from the text?
A.They have never been found in nature.
B.They do harm to cells, proteins and DNA.
C.They can slow down the damage of some cells.
D.They always keep balance with free radical.
4.What will the author probably tell us next?
A.What exactly oxidative stress is. B.How beauty marketers promote sales.
C.Where a variety of diseases come from. D.Whether free radicals can be prevented.
高三英语阅读理解中等难度题查看答案及解析
—Jack bought a new mobile phone the other day.
—_______?That’s his third one in just one month.
A.Had he B.Did he C.Does he D.Has he
高三英语单项填空中等难度题查看答案及解析
—Jack bought a new mobile phone the other day.
—_______?That’s his third one in just one month.
| A．Had he | B．Did he | C．Does he | D．Has he |
高三英语单项填空中等难度题查看答案及解析
--- It seems that Ann doesn't like the bag you bought for her the other day.
--- _______? I have been told she is desperate for one of that style.
A. If so B. How come
C. So what D. What if
高三英语单项填空中等难度题查看答案及解析
--- It seems that Ann doesn't like the bag you bought for her the other day.
--- _______? I have been told she is desperate for one of that style.
A. If so B. How come
C. So what D. What if
高三英语单项填空中等难度题查看答案及解析
— It seems that Ann doesn't like the bag you bought for her the other day.
—_______? I have been told she is desperate for one of that style.
A. If so B. How come C. So what D. What if
高三英语单项填空中等难度题查看答案及解析
--Have you heard of that? Tom recently bought a new car and an expensive flat.
--________? He even couldn’t have enough money to pay for the rent.
A. How about B. Why not C. How come D. So what
高三英语单项填空中等难度题查看答案及解析
— Have you heard of that?Tom recently bought a new car and an expensive flat.
— ________? He even couldn’t have enough money to pay for the rent.
| A．How about | B．Why not | C．How come | D．So what |
高三英语单项填空中等难度题查看答案及解析
The other day I was talking to a stranger on the bus; he told me that he had a good 36 in Chicago and he wondered if, by any chance, I 37 to know him . For a moment, I thought he might be 38 ,but I could tell from the expression on his face that he was not. He was 39 . I felt like saying that it was ridiculous (可笑的) to 40 that out of all the millions of people in Chicago I could possibly have ever bumped into his friend. But, 41 , I just smiled and reminded him that Chicago was a very 42 city. He nodded, and I thought he was going to be content to drop the subject and talk about something else. But I was wrong. He was silent for a few minutes, and then he 43 to tell me all about his friend.
His friend’s main 44 in life seemed to be tennis. He was an excellent tennis player , and he 45 had his own tennis court. There were a lot of people with swimming 46 , yet there were only two people with private tennis court; his friend in Chicago was one of them. I told him that I knew several 47 like that, including my brother, who was a doctor in California. He 48 that maybe there were more private courts in the country than he 49 but he did not know of any others. Then he asked me 50 my brother lived in California. When I said Sacramento, he said that was a coincidence 51 his Chicago friend spent the summer in Sacramento last year and he lived next door to a 52 who had a tennis court in his backyard. I said I felt that really was a coincidence (巧合) because my next-door neighbour had gone to Sacramento last summer and had 53 the house next to my brother’s house. For a moment, we stared at each other, but we did not say anything.
“Would your friend’s name happen to be Roland Kirkwood?” I asked finally. He 54 and said, “Yes. Would your brother’s name happen to be Dr Rey Hunter?” It was my 55 to laugh. “Yes,” I replied.
1.A. brother B. teacher C. friend D. neighbour
2.A. happened B. managed C. tried D. wanted
3.A. expecting B. lying C. talking D. joking
4.A. funny B. serious C. careful D. disappointed
5.A. find B. think C. realize D. see
6.A. indeed B. actually C. exactly D. instead
7.A. famous B. interesting C. big D. noisy
8.A. began B. stopped C. refused D. failed
9.A. problem B. choice C. interest D. work
10.A. just B. ever C. even D. surely
11.A. suit B. habit C. river D. pools
12.A. people B. players C strangers D. friends
13.A. advised B. admitted C. argued D. announced
14.A. recognized B. realized C. visited D. found
15.A. how B. whether C. where D. when
16.A. if B. because C. then D. though
17.A. doctor B. friend C. neighbour D. player
18.A.visited B. hired C. designed D. sold
19.A. smiled B. laughed C. cried D.nodded
20.A. chance B. pleasure C. turn D. time
高三英语完型填空中等难度题查看答案及解析
— Let’s have a game of tennis; the loser has to treat the other to an ice-cream.
— ________.
A. I’m afraid so B. It’s a deal C. You’ve got a point D. I suppose not
高三英语单项填空中等难度题查看答案及解析