The definition of the standard kilogram is fundamentally imperfect.Getting the definition right is a challenge that has tried the patience and intelligence of scientists for decades.
Scientists use just seven basic units to define all the other quantities we use - quantities such as speed，density，or electric power.All of those basic units except the kilogram are themselves defined in terms of natural properties that are beyond human control.
For example，the standard second （time） is defined as a specific number of vibration of a type of radiation released by atoms of a special metal.The standard meter （length），in turn，is defined as the length of the path light travels in a vacuum during a specific fraction of a second.
Not so the kilogram.This orphan of the basic unit family is simply the mass of a small platinum-iridium alloy cylinder（鉑-銥合金筒）locked away by the international Bureau of Weighs & Measures in France.
Embarrassingly，the last time the copies were brought for a checkup in the 1980s，officials found that some copies had gained about 20 parts per billion in weight compared to the master cylinder since the previous checkup in the 1940s.This implies that the master cylinder itself may be an inconstant standard.
No one knows what causes the weight changes.But the uncertainty can't be tolerated when precision in research and some manufacturing now demands accuracy to a few parts per billion.
Several efforts in several different countries are under way to redefine the kilogram in terms of basic physical quantities such as counting the actual number of atoms of a specific substance in a kilogram or the electromagnetic force that balances a kilogram mass against gravity.
A project of the latter type at the NIST laboratories in Gaithersburg hopes eventually to define mass in terms of electrical units.So far，none of these redefinition projects has borne fruit.They require precision of measurement and control of experimental conditions.The slightest pollution，tiny vibrations，or other influences - even changes in weather - can ruin results.You've got to hand it to scientists who are willing to devote many years to such painstaking but fundamentally important research.
（1）Which of the following best paragraphs the sentences "Not so the kilogram." in paragraph 4？CC
A．The kilogram is not as accurate as the standard second.
B．The kilogram is not universally accepted in the world.
C．The kilogram is not defined in terms of natural properties.
D．The kilogram is not well defined as time and length.
（2）The author introduced the examination of copies of platinum-iridium alloy cylinder in the 1980s to indicate that CC.
A．the cause of weight changes had been found
B．such kind of checkups had been carried out regularly
C．the changes in weight challenged the definition of kilogram
D．the consequences of such changes were significant in research
（3）According to the passage，to define the weight of mass in terms of electrical units DD.
A．is one of the best methods to redefine the kilogram
B．has been accepted as the only possible redefinition project
C．is not as difficult as what people can understand
D．has been considered by some scientists as a better approach
（4）We can known from the passage that the redefinition of the kilogram is BB.
A．more important in keeping market honesty
B．worth years of scientists' painstaking research
C．the urgent requirement of business and manufacturing
D．bringing about important and fruitful results
【答案】C；C；D；B
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發(fā)布：2024/5/27 14:0:0組卷：1引用：1難度：0.5
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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
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