Scientists have discovered how plants manage to live alongside each other in places that are dark and shady.Plants in the deep darkness of a thick forest，where natural supplies are not very great in amount，won't attempt to top their neighbors in growth as those in moderate（中 度 的）shade do.In deep shade conditions，it would be a waste of energy and harmful to survival because green shoots would never be able to top their larger neighbors in growth.
So how do plants prevent such growth in deep shade conditions？The secret lies in the clocks inside them，say scientists from the John Innes Centre and the University of Bristol.
They have discovered that when plants notice deep shade，this changes the expression of genes in certain parts of the circadian clock （晝夜節(jié)律時鐘）- the internal daily timer found in plants and other living things.These clock components perform an additional role in preventing plants from lengthening and overtopping neighbors.
The work identifies a previously unknown role of the circadian clock in controlling plant development，and the findings may have possible effects on both natural plant populations and crops.Professor Antony Dodd of the John Innes Centre said， "The biological clock of plants plays a big part in their development and fitness.This work casts new light on a new role of the circadian clock in adapting plants to competition with other plants in their environments." "It also gives us new insights into how plants adapt to very deep shade，where resources are very limited，" said Professor Kerry Franklin at the University of Bristol.
This work provides evidence for the stability of the circadian clock in stressful environments，and information that may be useful in developing new generations of crops in a challenging climate.
（1）What do plants normally do in moderate shade？ BB
A．Struggle to preserve energy.
B．Try to outgrow their neighbors.
C．Compete for limited resources.
D．Depend on each other to survive.
（2）How does the circadian clock affect plants？ DD
A．By changing their gene expression.
B．By making them realize light change.
C．By helping them adapt to the darkness.
D．By controlling their growth in deep shade.
（3）Why does the author write the text？ CC
A．To explain plants' secret of living in forests.
B．To introduce the role of the circadian clock.
C．To share a new discovery about plants.
D．To compare plants living in certain conditions.
（4）Which of the following could be the best title for the text？ CC
A．How plants face a challenging climate.
B．Why plants respond to different shade levels.
C．How plants become good neighbors in deep shade.
D．Why the circadian clock is vital to plants' growth.
【答案】B；D；C；C
【解答】
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發(fā)布：2024/5/27 14:0:0組卷：3引用：2難度：0.5
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1．Houses have been getting progressively "smarter" for decades，but the next generation of smart homes may offer what two Case Western Reserve University scientists are calling an "Internet of Ears".
Today's smart home features appliances，entertainment systems，security cameras and lighting，heating and cooling systems that are connected to each other and the Internet.They can be accessed and controlled remotely by computer or smartphone apps.
But a group of electrical engineering and computer science professors in the Case School of Engineering have been experimenting with a new suite of sensors （傳感器）.This system would read not only the vibrations （震動），sounds and even other movements associated with people and animals in a building，but also any slight changes in the existing electrical field.
While there still maybe a decade or so away，the home of the future could be a building that adjusts to your activity with only a few small，hidden sensors in the walls and floor without the need for monitoring cameras.
"We are trying to make a building that is able to 'listen' to the humans inside，" said Ming Chun Huang，an assistant professor in electrical engineering and computer science."We are using principles similar to those of the human ear，where vibrations are picked up and our algorithms （計算程序） recognise them to determine your specific movements.That's why we call it the 'Internet of Ears'."
"There is actually a constant 60 Hz electrical field all around us，and because people are somewhat conductive，they short out the field just a little，" Huang said."So，by measuring the disturbance in that field，we are able to determine their presence，or even their breathing，even when there are no vibrations associated with sound."
Huang said they have used as few as four small sensors in the walls and floor of a room.
As for privacy concerns，the system would not be able to identify individuals，although it could recognise people's different ways of walking.
（1）What uniqueness does the smart home of the next generation have？
A．It uses the advanced Internet technology.
B．It is controlled remotely by a computer.
C．It features appliances and entertainment systems.
D．It can read vibrations，sounds and movements.
（2）What's the key part of the system in the smart home？
A．The sensors.
B．The vibrations.
C．The electrical field.
D．The monitoring cameras.
（3）Which is the function of the smart home of the next generation？
A．Determining people's presence.
B．Recognising different people.
C．Protecting individuals' privacy.
D．Measuring the electrical field.
（4）What may be the best title for the text？
A．Various Smart Houses.
B．Benefits of Smart Houses.
C．How Do Smart Houses Work？
D．What Are Next Smart Homes Like？發(fā)布：2024/12/9 9:30:1組卷：22引用：1難度：0.7 -
2．Scientists say they have created a new device that can turn brain signals into electronic speech．The invention could one day give people who have lost the ability to speak a better way of communicating than current ones．
The device was developed by researchers from the University of California，San Francisco．Their results were recently published in a study in the journal Nature．Scientists created a "brain machine connection" that was set in the brain．The device was built to read and record brain signals that helped control the muscles to produce speech．These include the lips，tongue and jaw．
The study involved five volunteer patients who were being treated for epilepsy （癲癇）．The individuals had the ability speak and already had electrodes （電極） set in their brains．The volunteers were asked to read several hundred sentences aloud while the researchers recorded their brain activity．
The researchers used audio recordings to reproduce the vocal （發(fā)聲的） muscle movement which is the key to producing human speech．Future studies will test the technology on people who are unable to speak．
The study reports the reproduced sentences were understandable to hundreds of human listeners asked to write out what they heard．The listeners were able to write out 43 percent of sentences with perfect accuracy．
Edward Chang is a professor of the university's Well Institute．He was a lead researcher on the project．Chang admitted that much more research of the system would be needed to reach the goal of perfectly reproducing spoken language．
（1）Who will probably benefit most from this device？
A．Those unable to hear．
B．Those unable to see．
C．Those unable to speak．
D．Those unable to write．
（2）What do we know about the "brain machine connection"？
A．It could control the muscles．
B．It could produce human speech．
C．It could transform brain signals．
D．It could read and record brain signals．
（3）Which of the following is important for production of human speech？
A．Brain activity．
B．Muscle control．
C．Audio recording．
D．Vocal muscle movement．
（4）In which section of a newspaper may this text appear？
A．Science．
B．Fashion．
C．Education．
D．Entertainment．發(fā)布：2024/12/17 1:30:1組卷：9引用：4難度：0.7 -
3．A new study suggests that dark markings on the planet Mars represent sand —not water.The research in 2015 suggested that lines on some Martian hills were evidence of water.Yet American scientists now say these lines appear more like dry，flows of sand.If water is present，it is likely to be a small amount.Water in liquid form would be necessary for microbial（微生物的） life.
NASA，the American space agency，said more research is needed.Michael Meyer is the lead scientist for NASA's Mars exploration programme.He noted that the latest study does not reject the presence of water.But he admitted， "It just may not be as exciting as the idea of rivers going down the sides of cliffs（懸崖）."
The new findings come from a team led by Colin Dundas of the United States Geological Survey.His team measured 151 of these lines in 10 areas.Most of the lines end with slopes between 28 degrees and 35 degrees.These measurements are similar to active sand dunes（沙丘）on both Mars and Earth.A small covering of dust that moves and sometimes becomes lighter might help explain the markings.They usually appear in the Martian summertime，and then disappear until the next year.If these lines are dry .this suggests that recent Mars has not had large volumes of liquid water.Dundas and his research team say that many questions remain.
"I still think that Mars has a great potential for having had life early on in its history，" Meyer said. "As long as that's true，we also have a reasonable possibility of life still being on Mars.It just happens to be cryptic or well hidden."
NASA currently has no robotic vehicle—either on Mars or in development—with the ability to climb steep slopes.The lack of such equipment has engineers coming up with ideas like Martian helicopters or planes without pilots.
（1）What do American scientists find on Mars now according to their study？
A．A lot of little life.
B．An amount of water.
C．Some Martian hills.
D．Dark markings are sand.
（2）When do the markings come out？
A．In Martian spring.
B．In Martian summer.
C．In Martian autumn.
D．In Martian winter.
（3）What's Meyer's opinion about having life on Mars？
A．Doubtful.
B．Trustful.
C．Indifferent.
D．Objective.
（4）What does the underlined word "cryptic " in Paragraph 4 mean？
A．Undiscovered
B．Strange.
C．Magical.
D．Icy.發(fā)布：2024/12/3 12:0:1組卷：54引用：3難度：0.7
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