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In the earliest stages of man's development he had nomore need of money than animals have.He was content with very simple forms of shelter,made his own rough tools and weapons and could provide food and clothing for himself and his family from natural materials around him.As he became more civilized,however,he began to want better shelter,more efficient tools and weapons,and more comfortable and more lasting clothing than could be provided by his own neighborhood or by the work of his own unskilled hands.For these things he had to turn to the skilled people such as smiths,leather workers or carpenters.It was then that the question of payment arose.
At first he got what he wanted by a simple process ofexchange.The smith who had not the time to look after land or cattle was glad to take meat or grain from the farmer inexchange for an axe or a plough.But as more and more goods which had no fixed exchange value came on the market,exchange became too complicated to be satisfactory.Another problem arose when those who made things wanted to get stocks of wood or leather,or iron,but had nothing to offer in exchange until their finished goods were ready. Thus the difficulties of exchange led by degrees to the invention of money.In some countries easily handled things like seeds or shells were given a certain value and the farmer,instead of paying the smith for a new axe by giving him some meat or grain,gave him so many shells.If the smith had any shells left when he had bought his food,he could get stocks of the raw materials of his trade.In some countries quite large things such as cows or camels or even big flat stones were used for trade.Later,pieces of metal,bearing values according to the rarity of the metal and the size of the pieces,or coins were used.Money as we know it had arrived.
1.Exchange of goods became difficult because _________.
A man became more civilized
B smiths began to look after land or cattle in their spare time
C more and more goods which had no fixed exchange alues came to the
marker
D farmers hadn't enough grain or meat to provide for
skilled workers
2.Money was not used until _______.
A paper was invented
B people practiced a simple process of exchange
C nothing could be offered in exchangeD the exchange of one thing for another became too complicated
3.The best title for this passage is _____.
A What is money
B What are money's functions.
C The importance of money
D The beginning of money
Don't wash those fossils!
Standard museum practice can wash away DNA.
1.Washing, brushing and varnishing fossils — all standard conservation
treatments used by many fossil hunters and museum curators alike — vastly
reduces the chances of recovering ancient DNA.
2.Instead, excavators should be handling at least some of their bounty with
gloves, and freezing samples as they are found, dirt and all, concludes a paper
in the Proceedings of the National Academy of Sciences today.
3.Although many palaeontologists know anecdotally that this is the best way
to up the odds of extracting good DNA, Eva-Maria Geigl of the Jacques Monod
Institute in Paris, France, and her colleagues have now shown just how important
conservation practices can be.This information, they say, needs to be hammered
home among the people who are actually out in the field digging up bones.
4.Geigl and her colleagues looked at 3,200-year-old fossil bones belonging to
a single individual of an extinct cattle species, called an aurochs.The fossils
were dug up at a site in France at two different times — either in 1947, and
stored in a museum collection, or in 2004, and conserved in sterile conditions
at -20 oC.
5.The team's attempts to extract DNA from the 1947 bones all failed.The newly
excavated fossils, however, all yielded DNA.
6.Because the bones had been buried for the same amount of time, and in the
same conditions, the conservation method had to be to blame says Geigl."As much
DNA was degraded in these 57 years as in the 3,200 years before," she says.
Wash in, wash out
7.Because many palaeontologists base their work on the shape of fossils
alone, their methods of conservation are not designed to preserve DNA, Geigl
explains.
8.The biggest problem is how they are cleaned.Fossils are often washed
together on-site in a large bath, which can allow water — and contaminants in
the form of contemporary DNA — to permeate into the porous bones."Not only is
the authentic DNA getting washed out, but contamination is getting washed in,"
says Geigl.
9.Most ancient DNA specialists know this already, says Hendrik Poinar, an
evolutionary geneticist at McMaster University in Ontario, Canada.But that
doesn't mean that best practice has become widespread among those who actually
find the fossils.
10.Getting hold of fossils that have been preserved with their DNA in mind
relies on close relationships between lab-based geneticists and the excavators,
says palaeogeneticist Svante P bo of the Max Planck Institute for Evolutionary
Anthropology in Leipzig, Germany.And that only occurs in exceptional cases, he
says.
11.P bo's team, which has been sequencing Neanderthal DNA, continually faces
these problems."When you want to study ancient human and Neanderthal remains,
there's a big issue of contamination with contemporary human DNA," he says.
12.This doesn't mean that all museum specimens are fatally flawed, notes P
bo.The Neanderthal fossils that were recently sequenced in his own lab, for
example, had been part of a museum collection treated in the traditional way.But
P bo is keen to see samples of fossils from every major find preserved in line
with Geigl's recommendations — just in case.
Warm and wet
13.Geigl herself believes that, with cooperation between bench and field
researchers, preserving fossils properly could open up avenues of discovery that
have long been assumed closed.
14.Much human cultural development took place in temperate regions.DNA does
not survive well in warm environments in the first place, and can vanish when
fossils are washed and treated.For this reason, Geigl says, most ancient DNA
studies have been done on permafrost samples, such as the woolly mammoth, or on
remains sheltered from the elements in cold caves — including cave bear and
Neanderthal fossils.
15.Better conservation methods, and a focus on fresh fossils, could boost DNA
extraction from more delicate specimens, says Geigl.And that could shed more
light on the story of human evolution.
(640 words nature )
Glossary
Palaeontologists 古生物学家
Aurochs 欧洲野牛
Neanderthal (人类学)尼安德特人，旧石器时代的古人类。
Permafrost (地理)永冻层
Questions 1-6
Answer the following questions by using NO MORE THAN THREE WORDS for each
answer.
1.How did people traditionally treat fossils?
2.What suggestions do Geigl and her colleagues give on what should be done
when fossils are found?
3.What problems may be posed if fossil bones are washed on-site? Name
ONE.
4.What characteristic do fossil bones have to make them susceptible to be
contaminated with contemporary DNA when they are washed?
5.What could be better understood when conservation treatments are
improved?
6.The passage mentioned several animal species studied by researchers.How
many of them are mentioned?
Questions 7-11
Do the following statements agree with the information given in the passage?
Please write TRUE if the statement agrees with the writer FALSE if the statement
does not agree with the writer NOT GIVEN if there is no information about this
in the passage.
7.In their paper published in the Proceedings of the National Academy of
Sciences，Geigl and her colleagues have shown what conservation practices should
be followed to preserve ancient DNA.
8.The fossil bones that Geigl and her colleagues studied are all from the
same aurochs.
9.Geneticists don't have to work on site.
10.Only newly excavated fossil bones using new conservation methods suggested
by Geigl and her colleagues contain ancient DNA.
11.Paabo is still worried about the potential problems caused by treatments
of fossils in traditional way.
Questions 12-13
Complete the following the statements by choosing letter A-D for each
answer.
12.“This information” in paragraph 3 indicates:
[A] It is critical to follow proper practices in preserving ancient DNA.
[B] The best way of getting good DNA is to handle fossils with gloves.
[C] Fossil hunters should wear home-made hammers while digging up bones.
[D] Many palaeontologists know how one should do in treating fossils.
13.The study conducted by Geigl and her colleagues suggests:
[A] the fact that ancient DNA can not be recovered from fossil bones
excavated in the past.
[B] the correlation between the amount of burying time and that of the
recovered DNA.
[C] the pace at which DNA degrades.
[D] the correlation between conservation practices and degradation of
DNA.
new weapon to fight cancer
1. British scientists are preparing to launch trials of a radical new way to
fight cancer, which kills tumours by infecting them with viruses like the common
cold.
2. If successful, virus therapy could eventually form a third pillar
alongside radiotherapy and chemotherapy in the standard arsenal against cancer,
while avoiding some of the debilitating side-effects.
3. Leonard Seymour, a professor of gene therapy at Oxford University, who has
been working on the virus therapy with colleagues in London and the US, will
lead the trials later this year. Cancer Research UK said yesterday that it was
excited by the potential of Prof Seymour’s pioneering techniques.
4. One of the country’s leading geneticists, Prof Seymour has been working
with viruses that kill cancer cells directly, while avoiding harm to healthy
tissue. "In principle, you’ve got something which could be many times more
effective than regular chemotherapy," he said.
5. Cancer-killing viruses exploit the fact that cancer cells suppress the
body’s local immune system. "If a cancer doesn’t do that, the immune system
wipes it out. If you can get a virus into a tumour, viruses find them a very
good place to be because there’s no immune system to stop them replicating. You
can regard it as the cancer’s Achilles’ heel."
6. Only a small amount of the virus needs to get to the cancer. "They
replicate, you get a million copies in each cell and the cell bursts and they
infect the tumour cells adjacent and repeat the process," said Prof Seymour.
7. Preliminary research on mice shows that the viruses work well on tumours
resistant to standard cancer drugs. "It’s an interesting possibility that they
may have an advantage in killing drug-resistant tumours, which could be quite
different to anything we’ve had before."
8. Researchers have known for some time that viruses can kill tumour cells
and some aspects of the work have already been published in scientific journals.
American scientists have previously injected viruses directly into tumours but
this technique will not work if the cancer is inaccessible or has spread
throughout the body.
9. Prof Seymour’s innovative solution is to mask the virus from the body’s
immune system, effectively allowing the viruses to do what chemotherapy drugs do
- spread through the blood and reach tumours wherever they are. The big hurdle
has always been to find a way to deliver viruses to tumours via the bloodstream
without the body’s immune system destroying them on the way.
10. "What we’ve done is make chemical modifications to the virus to put a
polymer coat around it - it’s a stealth virus when you inject it," he said.
11. After the stealth virus infects the tumour, it replicates, but the copies
do not have the chemical modifications. If they escape from the tumour, the
copies will be quickly recognised and mopped up by the body’s immune system.
12. The therapy would be especially useful for secondary cancers, called
metastases, which sometimes spread around the body after the first tumour
appears. "There’s an awful statistic of patients in the west ... with malignant
cancers; 75% of them go on to die from metastases," said Prof Seymour.
13. Two viruses are likely to be examined in the first clinical trials:
adenovirus, which normally causes a cold-like illness, and vaccinia, which
causes cowpox and is also used in the vaccine against smallpox. For safety
reasons, both will be disabled to make them less pathogenic in the trial, but
Prof Seymour said he eventually hopes to use natural viruses.
14. The first trials will use uncoated adenovirus and vaccinia and will be
delivered locally to liver tumours, in order to establish whether the treatment
is safe in humans and what dose of virus will be needed. Several more years of
trials will be needed, eventually also on the polymer-coated viruses, before the
therapy can be considered for use in the NHS. Though the approach will be
examined at first for cancers that do not respond to conventional treatments,
Prof Seymour hopes that one day it might be applied to all cancers.
Questions 1-6
Do the following statements agree with the information given in the reading
passage? For questions 1-6 write
TRUE if the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if there is no information on this in the passage
1.Virus therapy, if successful, has an advantage in eliminating
side-effects.
2.Cancer Research UK is quite hopeful about Professor Seymour’s work on the
virus therapy.
3.Virus can kill cancer cells and stop them from growing again.
4.Cancer’s Achilles’ heel refers to the fact that virus may stay safely in a
tumor and replicate.
5.To infect the cancer cells, a good deal of viruses should be injected into
the tumor.
6.Researches on animals indicate that virus could be used as a new way to
treat drug-resistant tumors.
Question 7-9
Based on the reading passage, choose the appropriate letter from A-D for each
answer.
7.Information about researches on viruses killing tumor cells can be
found
(A) on TV
(B) in magazines
(C) on internet
(D) in newspapers
8.To treat tumors spreading out in body, researchers try to
(A) change the body’ immune system
(B) inject chemotherapy drugs into bloodstream.
(C) increase the amount of injection
(D) disguise the viruses on the way to tumors.
9.When the chemical modified virus in tumor replicates, the copies
(A) will soon escape from the tumor and spread out.
(B) will be wiped out by the body’s immune system.
(C) will be immediately recognized by the researchers.
(D) will eventually stop the tumor from spreading out.
Questions 10-13
Complete the sentences below. Choose your answers from the list of words. You
can only use each word once.
NB There are more words in the list than spaces so you will not use them
all.
In the first clinical trials, scientists will try to ……10…… adenovirus and
vaccinia, so both the viruses will be less pathogenic than the ……11…….These
uncoated viruses will be applied directly to certain areas to confirm safety on
human beings and the right ……12…… needed. The experiments will firstly be
……13……to the treatment of certain cancers
