Physical activity is important in preventing cardiovascular（心血管的）disease in young people so long as they don't undertake very intense activity on days when air pollution levels are high，according to a recently released study.
Until now，little has been known about the relationships between the health benefits of physical activity taking place outdoors and the potentially harmful effects of air pollution.Previous research by the authors of the current study had investigated the question in middle-aged people at a single point in time，but this is the first time that it has been investigated in young adults aged between 20-30 years over a period of several years.In addition，the researchers wanted to see what happens when people increase or decrease their physical activity over time.
At each health check-up，the participants completed a questionnaire asking about their physical activity in the past seven days and this information was changed into units of metabolic equivalent task（MET，代謝當量任務）minutes per week（MET-mins/week）.The participants were divided into four groups：0，1-499，500999 and 1000 or more MET-mins/week.People are recommended to do 500-999 MET-mins/week and this can be achieved by；for example，running，cycling or hiking for 15-30 minutes five times a week，or brisk walking，doubles tennis or slow cycling for 30-60 minutes five times a week.
The researchers used data to calculate annual average levels of air pollution，in particular the levels of small particulate matter tat are less than or equal to 10 or 2.5 microns in diameter，known a PM10 and PM25.
Overall，the results show that physical activity is associated with a lower risk of developing cardiovascular disease among young adults.However，when air pollution levels are high，exercising beyond the recommended amount may offset or even reverse the beneficial effects.The study cannot show that air pollution causes the increased cardiovascular risk，only that it is associated with it.
（1）What can we know from Paragraph 2？ CC
A．Outdoor physical activity harms our health.
B．Exercising isn't advised on serious air pollution days.
C．A first in-depth survey has been done on young adults.
D．Middle-aged people have been the ideal research target.
（2）How do the results come out？ AA
A．By doing research on young adults.
B．By collecting PM 10 and PM2.5 data.
C．By making experiments on middle-aged people.
D．By studying a questionnaire on physical activity.
（3）What do we know about the result？ BB
A．Air pollution leads to cardiovascular disease.
B．Cardiovascular disease relates to air pollution.
C．More physical exercise benefits young people.
D．Young adults seldom develop cardiovascular disease.
（4）What would be the best title for the passage？ AA
A．Physical activity & air pollution：when to do more or less physical activity
B．Physical activity & health benefit：how to prevent cardiovascular disease
C．Physical activity & air pollution：what to do with high air pollution levels
D．Physical activity &health benefit：how to maximize the health benefits of exercising
【考點】說明文．
【答案】C；A；B；A
【解答】
【點評】
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發(fā)布：2024/6/27 10:35:59組卷：2引用：1難度：0.5
相似題
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1．If you see a group of people dancing and singing on the street or in the railway station，you don't need to feel surprised.They are a flash mob（快閃族），which is a group of people who come together suddenly in a public place，do something unusual for a brief period of time，and then quickly break up.They are usually organized with the help of the Internet or other digital communication network.
At a predetermined time，they gather and perform some distractions（消遣）such as waving their hands and exchanging books.Then，they quickly break up before the police can arrive.Using mobile phones the flash mob can change its location if the first one has been replaced for any reason.
Bill Lasik，senior editor of Harper's Magazine，organized the first flash mob in Manhattan in May 2003 and the first successful flash mob came together on June 3，2003--after the first attempt was foiled at Macy's department store.Lasik claimed that the activity was designed to make fun of hipsters（時髦的人），and call attention to the cultural atmosphere.
Flash mob gatherings can sometimes shock people.Such an activity might seem amusing and untrue，but it also might frighten people who are not aware of what is taking place.Undoubtedly，flash mobs can serve as good political tools in any direction.They also have great economic potential，such as using flash mobs to advertise a product.
The flash mob is now becoming more and more popular.People use it to do many things.For example，in 2009，Michael Jackson's fans took part in a flash mob to remember him.Hundreds of his fans gathered singing and dancing Michael's famous song Beat It together.Flash mobs give people from all walks of life an opportunity to come together to create a memory.
（1）The underlined word "foiled" in Paragraph 2 can be replaced by "".
A．forgotten
B．prevented
C．a(chǎn)nnounced
D．confirmed
（2）What can you learn about the flash mob from the passage？
A．The flash mob usually breaks up quickly for lacking enough time.
B．Once the place for the activity is determined，it can't be changed.
C．The flash mob can be made use of in many fields for fun.
D．It gives people the chance to come together to do something unusual.
（3）The main purpose of the passage is to.
A．entertain
B．encourage
C．inform
D．persuade
（4）The writers attitude towards the flash mob is.
A．negative
B．objective
C．favorable
D．doubtful發(fā)布：2024/12/20 8:0:13組卷：17引用：2難度：0.5 -
2．The world is a greener place than it was 20 years ago．Recent NASA satellites data（2000-2017）have shown that human activities in China and India dominate this greening of the planet，thanks to ambitious tree-planting programmes in China and intensive agriculture in both countries．
The researchers from Boston University found that global green leaf area has increased by 5 percent in the new century，an area equal to all of the Amazon rainforest．China alone accounts for 25% of the global net increase in leaf area with only 6.6% of global vegetated area．China's contribution comes in large part from its programmes to conserve and expand forests，taking up about 42 percent of the greening．The greening from farmlands in China is about 32%，but that in India is about 82%．
Rama Nemani，a research scientist at NASA's Ames Research Centre and a co-author of the study said， "When the greening of the Earth was first observed，we thought it was due to a warmer，wetter climate and fertilization from the added carbon dioxide in the atmosphere．But with data from NASA satellites，scientists realized that humans are also contributing，which was all against our expectations．"
Nemani sees a positive message in the new findings． "Once people realize there is a problem，they tend to fix it，" he said． "In the 1970s and 1980s in India and China，the situation around vegetation loss was not good．In the 1990s，people realized it，and today things have improved．Humans are incredibly resilient．That is what we see in the satellite data．"
However，the researchers rang bells as well．They said that the gain in global greenness did not necessarily make up for the loss of natural vegetation in regions like Brazil and Indonesia．
（1）What is the second paragraph mainly about？
A．The decreasing size of the Amazon rainforest．
B．China's bigger contribution to global greening．
C．Total global green leaf area in the new century．
D．China's programmes to conserve and expand forests．
（2）What surprised scientists regarding global greening？
A．Human activities．
B．Suitable for analyzing data．
C．A warmer and wetter climate．
D．Carbon dioxide in the atmosphere．
（3）What does the underlined word "resilient" probably mean？
A．Good at making programmes．
B．Suitable for analyzing data．
C．Able to make corrections．
D．Active in planting trees．
（4）What does the last paragraph imply？
A．It is urgent to protect global natural resources．
B．Much remains to be done for global greenness．
C．Brazil and Indonesia lose most of their vegetation．
D．Global greenness needs all countries to work together．發(fā)布：2024/12/20 5:0:3組卷：7引用：1難度：0.6 -
3．Our dog Sandy is a golden retriever（尋回犬）.Once we performed an experiment to see how keen his nose was.There was one particular pile that must have had hundreds of sticks.We picked up one stick carved an X on it，walked away from the pile and then threw it back into the pile，not once but a dozen times into the pile.It was impossible for us to tell with any certainty which slick we had originally chosen.Each time he brought back that stick，It wasn't the shape or the size or the look of the stick that he used to pick it out from all the others.It was the smell we left on the stick.It is hard to imagine，hut for dogs every living creature has its own distinctive smell.
The noses of people have about 5 million cells that sense smell.Dogs' noses have anywhere from 125 to 300 million cells.Moreover，these cells are closer to the surface than cells in our noses，and more active.It has been estimated that dogs such as Sandy have noses that are a million times more sensitive than ours.Clothes that we haven't worn for weeks，and places we've only touched lightly indicate our presence to dogs.
His ears are also remarkable.He can hear sounds that humans can't and at distances which are astonishing.It is over our head to know and understand that world.Yet we have the advantage of being able to imagine what his experience is like，though he probably doesn't think too much about how we see the world.
The environment is the world that all living things share.Living creatures are born into the environment and are part of it.Yet there is no creature who perceives（感知到）all of what is and what happens.For a dog like Sandy a book isn't much different than a stick，whereas for us one stick is pretty much like every other stick.There is no one world experienced by all living creatures.
（1）Why did the author conduct the experiment？
A．To train Sandy to pick out sticks.
B．To show how fast Sandy found sticks.
C．To prove sensitivity of Sandy's nose.
D．To teach Sandy to tell different smells.
（2）What does the author intend to do in paragraph 2？
A．Support the conclusion with numbers.
B．Summarize the previous paragraph.
C．Provide some advice for the readers.
D．Introduce a new topic for discussion.
（3）What does the underlined idiom in paragraph 3 mean？
A．Amazing.
B．Difficult.
C．Reasonable.
D．Inconvenient.
（4）Which of the following best expresses the authors opinion in the last paragraph？
A．Worlds to experience.
B．An environment to share.
C．No environment，no creatures.
D．One environment，many worlds.發(fā)布：2024/12/18 14:30:1組卷：5引用：2難度：0.5
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