African crested rats（非洲黃冠鼠）-rabbit-sized furballs from East Africa-are finally starting to show their secrets.In 2011，scientists discovered that the rats laced their fur with a deadly poison.Now researchers report that these animals are surprisingly friendly toward each other and may even live in family groups.
Sara Weinstein，a biologist，was studying the poisonous rats but initially wasn't focused on their behavior. "The original goal was to look into the genetics（基因?qū)W）" she says.She wanted to understand how the-rats were able to apply poison to their fur without becoming sick.
The rats chew leaves and bark from poison arrow trees and apply their now-poisonous spit to their hair.The tree contains a class of chemicals that are very dangerous to most animals. "If we were to sit there and chew on one of these branches，we would certainly not be going about our normal activities，" Weinstein says.A person would probably throw up.And if someone consumed enough of the poison，their heart would stop beating.
But scientists didn't know how common the friendly behavior was in the rats since the 2011 report focused on just one animal.To study the rats，the research team set up cameras to capture images（捕捉影像）of the animals at night.But in 441 nights，the rats tripped the cameras' motion detectors only four times.The rats are probably too small and slow to set off the cameras，Weinstein says.
The scientists placed several of the animals in a "rat house"，a small cow shed with video cameras jye.aiside.In the 432 hours of rat videos with multiple rats in one space，the researchers could see how the rats interacted.At times，the animals would "comb" each other's fur.Sometimes，male and female rats formed a pair.A few of the adult rats also took care of young rats.The researchers think that these behaviors indicate that the animals might live in pairs that raise the young，as a family group.
（1）What had Sara Weinstein planned to study about African crested rats？ DD
A．Why they live together.
B．Their strange behavior.
C．How they survive alone.
D．The genetics about them.
（2）What can we know about the arrow trees？ DD
A．Most animals feed on their leaves.
B．A leaf of them is deadly to humans.
C．They make African crested rats throw up.
D．They are harmless to African crested rats.
（3）Why did the cameras fail to capture images of African crested rats at night？ AA
A．They seldom got started to work
B．The rats often knocked them down.
C．The rats were too small to notice.
D．It was too dark to take clear photos
（4）What did the researchers find about the African crested rats in the "rat house"？ CC
A．They quickly separated.
B．They hardly interacted.
C．They behaved socially.
D．They put themselves first.
【答案】D；D；A；C
【解答】
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發(fā)布：2024/4/20 14:35:0組卷：7引用：1難度：0.5
相似題
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1．Rainforests provide much of the world's oxygen.People have been trying to protect them for years.But another type of forest，the cloud forest，is just as important to humans.
These forests are at the tops of mountains，generally near the equator （赤道）.These wet，wooded mountaintops are mainly in African and Central and South American countries.They are called "cloud forests" because their height allows for the formation of clouds among the trees.The trees in these forests pull water out of the clouds.The water gathers on the leaves and falls into small rivers below，which flow into towns at the bottom of the mountain.The yearly rainfall in these areas is about 180 centimetres.Cloud forests can pull in up to 60 percent of that.The water is important to the plants and the people in the area.It helps them survive.
Cloud forests are also home to countless species of plants that can't be found anywhere else.One small cloud forest has as many types of plants as there are in all of Europe.In fact，there are so many that scientists haven't made a complete list of them yet.
These forests are being destroyed at increasing speed.Trees are being cut down，and roads are being built in their place.Some people have a goal to get government money to protect the forests.But they have had little success so far.Another way is to take the place of the destroyed plants with new ones.That，too，has been difficult because the plants are so special.There's plenty of work to be done，but saving the cloud forests is still possible with creative solutions.
（1）Where can you probably find cloud forests？
A．In North America.
B．Far from the equator.
C．In an African country.
D．At the foot of mountains.
（2）How much rainfall is pulled in by the cloud forests in those areas every year？
A．About 60 cm.
B．About 108 cm.
C．About 180 cm.
D．About 300 cm.
（3）What is the main idea of paragraph 3？
A．Europe is short of plant types.
B．Scientists are working on a list.
C．Cloud forests are getting smaller.
D．Cloud forests house many plants.
（4）What will be discussed in the following part of the text？
A．Ways to protect cloud forests.
B．Goals of cloud forest protectors.
C．Difficulties in planting new trees.
D．Successes of getting wide support.
（5）Where can we probably find the text？
A．In a storybook.
B．In a travel guide.
C．In a chemistry textbook.
D．In a geography magazine.發(fā)布：2025/1/1 18:0:1組卷：7引用：3難度：0.5 -
2．Photo Research "If you want to be a better photographer，stand in front of better stuff." Photographer Jim Richardson shared it with otjye.airs.He spends a great deal of time doing photo research，looking for great locations to shoot.
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"Above all，I'll look for places and events that are seasonal and timeless.I open my mind to what might make a great subject for a picture，" Jim said. "Most travelers tend to think only of places they're visiting，without looking deeper into culture，history or meaning.I try to get in time with the rhythm of the place and in tune with its melody.But most of all I just want to be ready.If I'm ready，I can just about count on being lucky."
（1）What does the underlined word "capture" in Paragraph 2 probably mean？
A．Identify.
B．Record.
C．Arrange.
D．Explore.
（2）What point does the author make about photographers in Paragraph 3？
A．They are unable to decide on the best plan of action.
B．It is possible for them to adopt flexible ways of working.
C．The third group is not as imaginative as some of the others.
D．Some of them refuse to try to understand the way others work.
（3）What is the main idea of Paragraph 4？
A．Sound preparation is a must for a satisfactory photo.
B．One should create photo sites in a photographic trip.
C．Taking photos requires vivid imagination in advance.
D．It is essential to do photo research in central locations.
（4）In the last paragraph，Jim states that.
A．he feels good to visit those historical places
B．he refuses to spend too much time in one place
C．he is careful about choosing the right place to visit
D．he likes to go to places that few people bother to visit發(fā)布：2025/1/1 18:0:1組卷：20引用：3難度：0.7 -
3．The baby is just one day old and has not yet left hospital．She is quiet but alert（警覺）．Twenty centimeters from her face researchers have placed a white card with two black spots on it．She stares at it carefully．A researcher removes the card and replaces it by another，this time with the spots differently spaced．As the cards change from one to the other，her gaze（凝視） starts to lose its focus - until a third，with three black spots，is presented．Her gaze returns；she looks at it for twice as long as she did at the previous card．Can she tell that the number two is different from three，just 24 hours after coming into the world？
Or do newborns simply prefer more to fewer？The same experiment，but with three spots shown before two，shows the same return of interest when the number of spots changes．Perhaps it is just the newness？When slightly older babies were shown cards with pictures of objects（a comb，a key，an orange and so on），changing the number of objects had an effect separate from changing the objects themselves．Could it be the pattern that two things make，as opposed to three？No again．Babies paid more attention to squares moving randomly on a screen when their number changed from two to three，or three to two．The effect even crosses between senses．Babies who were repeatedly shown two spots became more excited when they then heard three drumbeats than when they heard just two；likewise（同樣地） when the researchers started with drumbeats and moved to spots．
（1）The experiment described in Paragraph 1 is related to the baby's．
A．sense of hearing
B．sense of sight
C．sense of touch
D．sense of smell
（2）Babies are sensitive to the change in．
A．the size of cards
B．the colour of pictures
C．the shape of patterns
D．the number of objects
（3）Why did the researchers test the babies with drumbeats？
A．To reduce the difficulty of the experiment．
B．To see how babies recognize sounds．
C．To carry their experiment further．
D．To keep the babies' interest．
（4）Where does this text probably come from？
A．Science fiction．
B．Children's literature．
C．An advertisement．
D．A science report．發(fā)布：2025/1/1 17:0:1組卷：3引用：3難度：0.5
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