2019-2020年高考英语北师大版一轮复习课时作业：语言朋友（26）.doc

2019-2020年高考英语北师大版一轮复习课时作业：语言朋友（26）Expensive perfumes (香水) e in tiny bottles, but many hide a whale­sized secret.To perfect a particular smell, perfume­makers often use an ingredient that es from sperm whales, called ambergris.But using ambergris, which helps a perfume last longer, is strongly opposed by many people who think it is wrong to kill whales just so we can smell sweet.Joerg Bohlmann is neither a perfumer nor a whale expert.He's a plant biologist at the University of British Columbia in Canada.But his discovery of a new plant gene (基因) might push whales out of the perfume business.The gene es from fir trees, found throughout North America and monly used as Christmas trees.The trees produce a chemical that can be used in perfume in place of ambergris－but with_a_catch．“There's a problem that many people wouldn't consider.In the tree, the chemical is mixed with many others.That makes separation a challenge，” Bohlmann says.“It's like trying to isolate sugar from a biscuit.” This is where science bees useful.When Bohlmann learned that fir trees produce the ambergris­like chemical, he decided to use his gene know­how to find the instructions for how to make the ambergris­substitute.Bohlmann found that gene and took it out of the tree cells.Then he did something that might sound strange to someone who doesn't work in genetics: Bohlmann put the gene from the tree into yeast (酵母) cells.Yeast may sound familiar because it's used to make things like bread, wine and beer.Biologists like to work with yeast because it easily adopts new genes and changes its features and behaviour.When Bohlmann put the fir tree gene into the yeast, the yeast started making the same chemical that had been produced by the tree.Perfumers pay big money for ambergris because it is a fixative, which means it holds a smell in place on a person's body.“Cheap perfumes smell good in the first hour or so and then everything is gone，” explains Bohlmann.“But expensive perfumes are much more stable.Their smell lasts much longer, for hours or even a day after you apply them.” The new chemical, made from the tree genes, can be used as a fixative, too.And using yeast to make it is far cheaper than acquiring ambergris.Bohlmann admits he never thought he'd get into the perfume business.But now, he says, producers have been calling to find out how to use his technology in new perfumes.解题导语：制作香水需要从鲸鱼里提取龙涎香，生物学家约尔格·博尔曼最近发现枞树里有一种物质可以代替龙涎香。

1．It can be inferred from the passage that if a perfume contains ambergris，________．A．its user probably supports whale huntingB．its smell will last for about an hourC．there will be a whale symbol on the bottleD．it is probably very expensive解析：推理判断题根据第二段“perfume­makers often use an ingredient that es from sperm whales, called ambergris.”可知来自抹香鲸的龙涎香应该很贵，故选D答案：D2．The underlined expression “with a catch” in Paragraph 3 means________．A．being difficult to holdB．having a hidden problemC．needing further testingD．being too similar解析：词义猜测题。

根据下文“There's a problem that many people wouldn't consider.”可知有一个不为人知的问题即隐藏的问题，故选B答案：B3．According to the passage, why are yeast cells often used in genetic research?A．They can take on the characteristics of other genes.B．They can reproduce much faster than other cells.C．They share some of the qualities of plant genes.D．They're much cheaper to use than ambergris.解析：细节理解题根据第七段“Biologists like to work with yeast because it easily adopts new genes and changes its features and behaviour.”可知因为它们能呈现出其他基因的特征，故选A。

答案：A4．What can we learn about Joerg Bohlmann from the passage?A．He is opposed to whale hunting.B．He made his discovery during Christmas.C．He has worked in the perfume industry for many years.D．He has previously done genetic research.解析：细节理解题根据文章内容可知Bohlmann以前做过基因研究工作，故选D答案：D5．What is the best title for the passage?A．The Christmas tree's secret.B．The sweet smell of success.C．Whale­free perfume.D．Save the whale.解析：主旨归纳题根据全文的内容可知，这个研究成果的运用可不再需要从鲸里提取龙涎香制作香水，把鲸鱼解放了，故选C答案：C语法填空On her 80th birthday，Nobel Prize­winning author Pearl Buck was asked if she wished to be young again.She quickly replied，“Wish to be young again? No，for I have learned too much to lose if I am a far6.________(value)person today than I was 30 years ago，or 20 years ago，or 15，10 or even 5.I have learnt so much 7.________I was 70.”Buck understood that life isn't meant to be lived on bell curve(钟形曲线)．We don't go up for a while and then，after a certain age，begin a downhill slide.8.________，we are able to continue on an upward trend.And one of the most significant ways we can do that is by learning from the lives of9.________－especially children.When we take time10.________(share)what we've learned with the children in our lives, we offer them something11.________they can get nowhere else－the treasure of experience.When I think back to the many positive influences on12.________childhood，I recognize that some of the greates。