The Mystery of Why Sunflowers Turn to Follow the Sun—Solved Scientists have answered a burning question central to sunflowers：Why do young flowers always face the sun over the course of a day？
And also：Once sunflowers become full-grown，why do they stop tracking the sun and only face east？
In a newly-published article，researchers claim that a young plant's sun-tracking （also called heliotropism）can be explained by circadian rhythms—the behavioural changes tied to an internal clock that humans also have，which generally follows a 24-hour cycle.
"Growth rates on the east side were high during the day and very low at night，whereas growth rates on the west side were low during the day and higher at night，" the journal article says.
The researchers tied plants up so they couldn't move or turned them away from the sun—and they found those flowers eventually had "fewer organic materials and less leaf area" than flowers that could move with the sun.
Full-grown sunflowers respond differently to the sun.According to the article，"As overall growth slows down，the circadian clock ensures that the plant reacts more strongly to light early in the morning than in the afternoon or evening，so it gradually stops moving westward during the day."
The researchers compared full-grown flowers facing east with those they turned to face west，and found that east-facing flowers attracted five times as many helpful pollinators.That's because the east-facing flowers heat up faster and bees like warm flowers.
"Just like people，plants depend on the daily rhythms of day and night to function，" Anne Sylvester，director of the National Science Foundation's Plant Genome（基因組） Research Programme said in a press release. "Sunflowers，like solar panels，follow the sun from east to west.These researchers explore information in the sunflower genome to understand how and why sunflowers track the sun."
UC Berkeley professor and co-author of the study，Benjamin Blackman，believes that the connection between circadian rhythms and growth could be applicable to other researches. "The more general point，that one of the circadian clock's adaptive functions is to regulate the timing and strength of growth responses to environmental signals，is one that I think will apply to a broad range of qualities and species，" he said.
（1）What did the researchers discover when they tied the sunflowers up？ CC
A．They still tracked and faced towards the sun.
B．They grew faster during the daytime than they did at night.
C．Their growth rates were lower than those of flowers facing the sun.
D．The growth rates on the west side were higher than those on the east.
（2）Why do sunflowers move westward less when they are fully-grown？ DD
A．Because they will not be affected by light anymore.
B．Because they would stop growing up if they faced west.
C．Because they are not active at all during afternoons or evenings.
D．Because they are more sensitive to light in the early morning from the east.
（3）What may the underlined word "pollinators" （Para.7）refer to？ AA
A．Bees.
B．Plants.
C．Energy.
D．Researchers.
（4）What is the possible direction of future study，according to Benjamin Blackman？ DD
A．Exploring information in the sunflower genome.
B．Comparing human's circadian rhythms with sunflowers'.
C．Comparing full-grown flowers facing east with those facing west.
D．Exploring how circadian rhythms affect the growth of other species.
【答案】C；D；A；D
【解答】
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發(fā)布：2024/4/20 14:35:0組卷：20引用：1難度：0.3
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1．British children's writer Roald Dahl ate chocolates and sweets "pretty much every mealtime"，remembers daughter Ophelia Dahl．
After dinner，whether dining alone or entertaining guests，Dahl would pass around a little red plastic box full of Mars Bars，Milky Ways，Maltesers，Kit Kats and much more．
He knew the history of all the sweets and could tell you exactly when they were invented．1937 was a big year when Kit Kats （his favorite），Rolos and Smarties （his dog，chopper's favorite） were invented．He wrote a history of chocolate，lecturing schoolchildren to commit such dates to memory（熟記），such as 1928 when "Cadbury's Fruit and Nut Bar popped up on the scene"，saying． "Don't bother with the Kings and Queens of England．All of you should learn these dates instead．Perhaps the Headmistress（女校長）will see from now on that it becomes part of the major teaching in this school．"
According to Dahl，the Golden Years of Chocolate were 1930-1937．In 1930，Roald Dahl was 14 years old．He was a student at Repton，a famous boys' boarding school in England．It was a tough environment：those in authority were more interested in controlling than educating the students．
Ironically（諷刺地），it was at this difficult period that chocolate became Dahl's passion．Near Repton was a Cadbury chocolate factory．Every so often，Cadbury would send each schoolboy a sampler（樣品）box of new chocolates to taste and grade．They were using the students---"the greatest chocolate bar experts in the world to test out their new inventions．
This was when Dahl's imagination took flight．He pictured factories with inventing rooms with pots of chocolate and fudge（軟糖）and "all sorts of other delicious fillings bubbling away on the stoves"．
"It was lovely dreaming those dreams…when I was looking for a plot for my second book for children．I remembered those little cardboard boxes（紙盒）and the newly invented chocolates inside them，and I began to write a book called Charlie and the Chocolate Factory．"
For the record，Roald Dahl did not like chocolate cake or chocolate ice cream．He said， "I prefer my chocolate straight．"
（1）What's the purpose of the first paragraph？
A．To introduce the main topic---Roald Dahl．
B．To introduce Dahl's love for chocolate．
C．To introduce main character's daily life．
D．To introduce some important characters．
（2）What can we infer from the passage about Roald Dahl？
A．He treated himself with various chocolate after dinner secretly．
B．He has a good knowledge of chocolate，especially its history．
C．He used to lecture schoolchildren of a boys' boarding school．
D．He only wrote some books related to the history of chocolate．
（3）What happened during the Golden Years of Chocolate？
A．It was a great time for children to get educated．
B．Those years stopped Dahl's interest in chocolate．
C．Students could become chocolate experts then．
D．Roald Dahl's passion for chocolate was lit up then．
（4）gave Roald Dahl inspiration to write Charlie and Chocolate Factory．
A．the dream about chocolates．
B．Factories with chocolate and fudge．
C．Those boxes with chocolate．
D．Chocolate cakes and ice cream發(fā)布：2025/1/30 8:0:1組卷：0引用：1難度：0.5 -
2．Recently，a film star has been giving away free books on the London Underground．If you're a bookworm，a Harry Potter fan and a London Underground user，then it's been an exciting month for you．
Emma Watson，who starred in films based on the novels about a fictional schoolboy wizard，has been hiding books on the Tube for passengers to read through．
It's part of he Book On The Underground movement，which has a simple aim：to get more people burying themselves in literature．Books are left on trains for passengers to pick up，dip into and then leave for another lucky reader to skim．
The movement started in 2012 and drops off about 150 books a week in stations across London．Talking about Watson's participation in the project，the manager of Books On The Under ground，Cornelia Oxley，said， "The reaction has been great．It must be a mixture of how much everyone admires Emma，and how exciting it is to find something as wonderful as a new book on your journey．"
The 100 or so books Watson left for passengers to read were even more special because she left a hand-written inscription（題詞）．The books were Kaya Angelou's Mom & Me & Mom．
One person who discovered a copy of the book on the Tube said she felt like the character Charlie Bucket - a boy who finds a golden ticket to the world's greatest chocolate factory - in the Roald Dahl's classic，Charlie and the Chocolate Factory Watson became a UN Women Goodwill Ambassador in the summer of 2014 and has since started reading as many books and essays on equality and feminism（饑荒） as possible．She has also started her own book club．
So．Why not take a leaf out of Emma Watson's book and leave a copy of your favorite book on a train？It could make a stranger's life richer．
（1）What does Books On The Underground aim to do？
A．To get more readers to buy their books．
B．To leave books on trains．
C．To find lucky readers．
D．To get more people to read．
（2）Which of the following statements is NOT true？
A．People's admiration for Emma Watson contributes to the success of the movement．
B．There is a golden ticket to the world's greatest chocolate factory in the book．
C．To find something wonderful on a journey is exciting．
D．Emma Watson left hand-written inscriptions on the books．
（3）What's the author's attitude towards Emma Watson's leaving books on the train？
A．critical
B．indifferent
C．supportive
D．pessimistic發(fā)布：2025/1/30 8:0:1組卷：0引用：1難度：0.5 -
3．It can be really hard to learn a new language．I had always enjoyed learning languages in school，but only recently did I start learning German．I found that I could understand and learn individual words easily，but when it came to literature，I really struggled．That was when my tutor at university suggested reading some children's books printed in the target language．
At first，I felt a bit silly going on a hunt for a book designed for someone half my age，but then I realised that everyone has to start somewhere．As children，we are given these basic texts to familiarise our brains with certain vocabulary and writing structures，and from there，we can learn and develop．I started with books which are taught to us as children in the UK．I managed to find Oliver Twist by Charles Dickens and James and the Giant Peach by Roald Dahl．
The beauty of reading books that were introduced to you as a child is that you are already familiar with the plot．Therefore you can work out some words with your knowledge of the story．At first，I used to read with the book in one hand and a dictionary in the other，but this did not work well．The method I would recommend is to read a chapter first and at the end of that chapter，highlight the new words and then look up the definitions．If you can wait a bit before using a dictionary，you may be surprised what you can understand merely from the context．Additionally，a lot of children's books have pictures which may give you a clue as to what or to whom the passage is referring．
If you can find a translation of the books you have read as a child，I would strongly advise reading those if you are a complete beginner．However，if you feel a bit more confident reading in English，I would personally recommend the series of 'Harry Potter' books by J．K．Rowling or any of the Roald Dahl children's books．
（1）What makes it hard for the author to learn German？
A．The author had a poor memory．
B．The author had no interest in it．
C．The author had no one to ask for help．
D．The author couldn't read books fluently．
（2）What did the author think of reading children's books in the target language at first？
A．Interesting．
B．Stupid．
C．Helpful．
D．Boring．
（3）What does the author try to express mainly in Paragraph 3？
A．How to deal with new words while reading．
B．Why it is helpful to read children's book at first．
C．How to choose a proper book to match your level．
D．How to form the habit of reading in the target language．
（4）Why does the author write this text？
A．To give tips on how to learn a new language．
B．To persuade the readers to learn a new language．
C．To stress the importance of reading in language learning．
D．To share the author's stories of learning a new language．發(fā)布：2025/1/30 8:0:1組卷：5引用：1難度：0.5