Special trees that grow faster, fight pollution, produce better wood, and even sense chemical attacks are being planted by scientists in the US．
When 40 per cent of Hawaii's US$14 million-a-year papaya （木瓜）industry was destroyed by a virus five years ago, work began on creating genetically engineered（轉(zhuǎn)基因的）trees．
Researchers successfully introduced seeds that were designed to resist the virus．Since then, more and more people have been testing genetically engineered trees．Some researchers put special bacteria into trees to help them grow faster and produce better wood．Others are trying to create trees that can clean polluted soil．Meanwhile fruit farmers are looking for trees that are strong enough to resist worms, and paper companies want trees that produce more wood and therefore more paper．
The Pentagon （五角大樓） even gave the researchers US$500,000 this year after they developed a pine tree that changes its colours if it senses a chemical attack．So far, the poplar, eucalyptus （楊樹與桉樹）, apple and coffee trees are among those being engineered．All this can be done today because we have a better understanding of tree genomes （基因組）．
However, some people fear that the genetically engineered trees will cause dangerous results．They are worried that the new trees will breed with natural species and change the balance of the forest environment．
“It could be destructive,” said Jim Diamond, an environmentalist. “Trees are what is left of our natural environment and home to many endangered species.”
But researchers insist that science could give nature a fighting chance against both natural and man-made dangers．They hope to answer the critics by stopping the new trees from breeding, so their effect on the environment can be controlled．
63．Which kind of tree is not the ones that scientists are planting in the US?
A．Trees that worms can't hurt．
B．Genetically engineered trees．
C．Trees that can resist wind better．
D．Trees that can protect themselves at a chemical attack．
64．What caused the American scientists to work on special trees?
A．Tree genomes are mapped out so scientists know how to improve trees．
B．Great numbers of trees have been lost due to attacks by viruses．
C．Researchers successfully introduced seeds designed to resist the virus．
D．They think science could give nature a fighting chance against both natural and man-made dangers．
65．Which of the following was probably the first kind of trees being engineered?
A．Papaya．                     B．Pine．                          C．Apple．                        D．Poplar．
66．Why did critics think engineered trees dangerous? Because ________．
A．these trees can destroy the balance of nature
B．everything except trees has been genetically engineered
C．trees are home to many endangered species
D．these trees may affect normal trees


【小題1】C
【小題2】B
【小題3】A
【小題4】D

解析

練習(xí)冊系列答案
相關(guān)習(xí)題

科目：高中英語 來源：高考三人行·英語 題型：014

These bears feed ________ the leaves of this special tree.

[　　]

A．to
B．on
C．with
D．up

查看答案和解析>>

科目：高中英語 來源： 題型：閱讀理解

New Year and Its Celebrations（新年習(xí)俗）?
January 1,the beginning of a New Year.?
As far back in history as we can tell ,people have celebrated（慶祝）the start of a New Year .The people of ancient Egypt began their New Year in summer .That is when the Nile River flooded its banks bringing water and fertility（肥沃）to the land .The people of ancient Babylon（巴比倫）and Persia（波斯）began their New Year on March 21,the first day of spring .And some native American Indians（美洲土著印第安人）began their New Year when the nuts of the oak（橡木）tree became ripe .That was usually in late summer.?
Now almost everyone celebrates New Year's Day on January 1,the day as before people observed the New Year's holiday in many different ways .The ancient Babylonains celebrated it by forcing their king to give up his crown（王冠） and royal（皇家） clothing. They made him get down on his knees and admit all the mistakes he had made during the past year. This idea of admitting wrongs and finishing the business of the old year is found in many societies at new year.?
So is the idea of making resolutions（決定）.The resolution is a promise to change your ways ,to stop smoking ,for example ,or to get more physical exercise.?
Noise making is another ancient custom at the New Year .The noise is considered necessary to chase away（趕走） the evil（邪惡） spirits of the old year .People around the world do different things to make a lot of noise .They may hit sticks together ,beat on drums（鼓）,blow horns（號）,or explode fire-works（煙火）.?
Americans celebrate the New Year in many ways .Most do not have to go to work or school .So they visit family and friends ,attend church services ,share a holiday meal ,or watch New Year's parades（游行） on television. Most years university teams play in special holiday games .For those who have been busy at work or school ,new year may be a day of rest .They spend the time thinking about and preparing for the demands of the New Year.?
1.Which of the following statements is right??
A.The people of ancient Egypt began their New Year in spring.?
B.The people of ancient Babylon began their New Year on March 21,the first day of spring.?
C.Some native American Indians began their New Year in early summer.?
D.The people of ancient Persia began their New Year in late summer.?
2.Why do people make a lot of noise on the New Year according to the passage??
A.The noise is considered necessary to frighten the evil spirits of the old year.
B.The noise is considered necessary to show people's excitement.?
C.The noise is considered a symbol of admitting all the mistakes one did in the past year.?
D.People have no other better ways to show their happiness.?
3.Americans celebrate the New Year by doing things as follows except ________.
A.resting at home?
B.visiting family and friends?
C.attending church services?
D.having sports and games?

查看答案和解析>>

科目：高中英語 來源：河南省唐河三高2009-2010學(xué)年高一下學(xué)期期末模擬試題（英語） 題型：閱讀理解

Do you know why different animals or pests have their special colours? Colours in them seem to be used mainly to protect themselves.

Some birds like eating locusts. but birds cannot easily catch them. Why? It is because locusts change their colours together with the change of the colours of crops. When crops are green, locusts look green. But as the harvest time comes, locusts change to the same brown colour as crops have. Some other pests with different colours from plants are easily found and eaten by others. So they have to hide themselves for lives and appear only at night.

If you study the animal life, you'll find the main use of colouring is protecting themselves. Bears, lions and other animals move quietly through forests. They cannot be seen by hunters. This is because they have the colours much like the tree.

Have you ever noticed an even more strange act? A kind of fish in the sea can send out a kind of very black liquid when it faces danger. While the liquid spread over, the enemies cannot find it. And it immediately swims away. So it has lived up to now though it isn't strong at all.

1. From the passage we learn that locusts ___ .

A. are small animals

B. are easily found by birds

C. are dangerous to their enemies

D. change their colours to protect themselves

2 How can pests with different colours from plants keep out of danger?

A. They run away quickly.

B. They colours much like their enemies.

C. They hide themselves in the day and appear at night.

D. They have to move quietly.

3. Bears and lions can keep safe because they ___ .

A. have the colours much like the trees   B. move quickly

C. like brown and grey colours         D. live in forests

4. Which is the best title for this passage?

A. The Change of Colours for Animals and Pests

B. Colours of Different Animals and Pests

C. The Main Use of Colours for Animals and Pests

D. Some Animals and Pests

 

查看答案和解析>>

科目：高中英語 來源：2013屆浙江省高二上學(xué)期期中考試英語試卷 題型：閱讀理解

Coffee experts are willing to pay large sums of money for high-quality coffee beans. The high-end beans, such as Kona or Blue Mountain, are known to cost extraordinary sums of money. Then there is Kopi Lowak (translated as “Civet Coffee”), the world’s most expensive coffee, which sells for as much as US $50 per quarter-pound.

This isn’t particularly surprising, because approximately 500 pounds a year of Kopi Lowak make up the entire world supply. What is surprising is why this particular coffee is so rare. In fact, it’s not the plants that are rare. It’s the civet droppings. That’s right, the civet droppings—the body waste of the palm civet. Coffee beans aren’t Kopi Lowak until they’ve been digested(消化) and come out in the body waste of the palm civet.

Palm civets are tree-dwelling, raccoon-like little animals, native to Southeast Asia and the Indonesian islands. They also have a love for coffee cherries. According to Kopi Lowak suppliers, palm civets eat the fruit whole, but only digest the outer fruit, leaving the beans intact(完好無損). While the beans are not destroyed, they undergo a transformation in the animal’s body. A chemical substance in the digestive system of the palm civet causes some changes to the beans to give them a unique flavor(味道). However, this is not the only explanation why coffee beans retrieved from civet droppings have a special flavor all their own. Another possible reason is that palm civets have an unfailing instinct for picking the coffee cherries at the peak of their ripeness.

Kopi Lowak is reported to have a character in taste unlike any other coffee, complex with caramel undertones and an earthy flavor. Currently, most of the world’s supply of Kopi Lowak is sold in Japan, though a few US markets are also starting to stock up on Kopi Lowak.

1.What does “This” in the second paragraph refer to?

A. Civet Coffee.                            B. Blue Mountain coffee.

C. The high price of Kopi Lowak.            D. The unique taste of Kona.

2.Why is Kopi Lowak expensive?

A. There is a very limited supply of the beans.

B. The coffee trees that grow the beans are scarce.

C. It takes a long time for the coffee beans to ripen.

D. Only a few experts know how to produce the beans.

3.What is the main point discussed in the third paragraph?

A. Why palm civets like the coffee beans.

B. Where Kopi Lowak is mainly harvested.

C. What chemicals are found in the civet’s digestive system.

D. How palm civets change coffee fruit to Kopi Lowak beans.

4.Which of the following statements is true, according to the passage?

A. Little palm civets eat only the outer layer of the coffee cherries.

B. Palm civets somehow know the right time when the coffee fruit ripens.

C. Kopi Lowak is most popular in Southeast Asia and the Indonesian islands.

D. Kona and Blue Mountain are the most expensive coffees but only of average quality.

 

查看答案和解析>>

科目：高中英語 來源：2012屆海南省高二上學(xué)期期末考試英語卷（重點班） 題型：閱讀理解

Bats are the only mammals(哺乳動物) which can fly properly. Other flying mammals have wings of thin skin which cover their sides between their front and back legs. They can only fly from tree to tree, but they cannot change direction when they want to.

All bats fly at night and most of them hunt for flying insects(昆蟲), such as bees. The common bat finds its food by making a constant noise that the human ear cannot hear. The bat listens for echoes(回聲) of the noise as it bounces(反射) off the insects showing the bat their position.

The Fruit bat feeds on many different kinds of fruit. It does not use echoes but instead has very large, special eyes to see even in low light. The largest Fruit bat has a wing length of 0.75 meters. The Vampire bat drinks the blood of large mammals, and a few bats catch fish, birds and even other bats.

1. Some flying mammals are not real flyers because _____.

 A. they do not have wings                     B. their wings are too thin

C. they have skin between their legs             D. they cannot turn around in the air

2. When common bats hunt for food they _____.

   A. use echoes to kill the insects           B. make a noise to draw insects to them

C. produce a sound and listen to the echoes     D. listen noise made by the insects

3. Unlike other bats, the Fruit bat _____.

   A. can see very well                   B. eats fruit and fish 

C. has very long wings                    D. has excellent hearings

4.The word "it" in the second paragraph refers to _____.

   A. the bat           B. the echo      C. the noise       D. the insect

 

 

查看答案和解析>>

同步練習(xí)冊答案