相关试题
共用题干
Giant Structures
It is an impossible task to select the most amazing wonders of the modern world since every year more______(1)constructions appear. Here are three giant structures which are worthy of our admiration______(2)they may have been surpassed by some more recent wonders.
The Petronas Twin Towers
The Petronas Towers were the tallest buildings in the world when they were completed in 1999.______(3)a height of 452 metres,the tall twin towers,like two thin pencils,dominate the city of Kuala Lumpur. At the 41st floor,the towers are______(4)by a bridge,symbolizing a gateway to the city. The American architect Cesar Pelli designed the skyscrapers.
Constructed of high-strength concrete,the building______(5)around 1,800 square metres of office space on every floor. And it has a shopping centre and a concert hall at the base.Other______(6)of this impressive building include double-decker lifts,and glass and steel sunshades.
The Millau Bridge
The Millau Bridge was opened in 2004 in the Tarn Valley,in southern France. At the ______(7)it was built,it was the world,5 highest bridge,______(8)over 340m at the highest point. The bridge is described as one of the most amazingly beautiful bridges in the world. It was built to ________ (9) Millau's congestion（拥堵）problems. The congestion was then caused by traffic passing from Paris to Barcelona in Spain. The bridge was built to with-stand the______(10) extreme seismic（地震的）and climatic conditions. Besides , it is guar- anteed for 120 years!
The Itaipu Dam
The Itaipu hydroelectric power plant is one of the largest constructions of its kind in the world.
It______(11)of a series of dams across the River Parana,______(12)forms a natural border between Brazil and Paraguay. Started in 1975 and taking 16 years to complete, the construction was carried out as a joint project between the two______(13).The dam is well-known for both its electricity output and its size. In 1995 it produced 78% of Paraguay's and 25% Of Brazil's______(14)needs. In its construction,the amount of iron and steel used was equivalent to over 300 Eiffel Towers.It is a______(15)amazing wonder of engineering.
6._________
A: features
B: types
C: tasks
D: roles
共用题干
Smoking can Increase Depressive Symptoms in Teens
While some teenagers may use cigarettes to "self-medicate"（自我治疗）against the blues（忧郁）,sci-
entists at the University of Toronto and the University of Montreal have found that smoking may actually
______________
(51)depressive symptoms in some teens.
"This observational study is one of the few to examine the perceived ______________(52)benefits of
smoking among teens,"says lead researcher Michael Chaiton,a research associate at the Ontario Tobacco
Research Unit of the University of Toronto."_______________(53)cigarettes may appear to have self-medicating
effects or to improve mood,in the long_______________(54)we found that teens who started to smoke reported
higher depressive symptoms."
As part of the study,some 662 high school teenagers completed up to 20 questionnaires about their use
of cigarettes to ______________
(55)mood.Secondary schools were selected to provide a mix of French and
English participants,urban and rural schools,and schools ______________(56)in high,moderate and low so-
cioeconomic neighbourhoods.
Participants were divided into three
______________ (57):never smokers;smokers who did not use ciga-
rettes to self-medicate,improve mood or physical
______________ (58);smokers who used cigarettes to self-
medicate.Depressive symptoms were measured using a scale that asked how often participants felt too tired
to do things;had
______________ (59)going to sleep or staying asleep;felt unhappy,sad,or depressed;felt
hopeless about the future;felt anxious or tense;and worried too much about things.
" Smokers who used cigarettes as mood
______________( 60 ) had higher risks of elevated（提升）depres-
sive symptoms______________ (61)teens who had never smoked,"says co-researcher Jennifer O'Loughlin,a
professor at the University of Montreal Department of Social and Preventive Medicine."Our study found that
teen smokers who reported emotional benefits from smoking are_______________(62)higher risk of developing
depressive symptoms."
The______________ (63)between depression and'smoking exists______________(64)among teens that use
cigarettes to feel better."It's ______________(65)to emphasize that depressive symptom scores were higher
among teenagers who reported emotional benefits from smoking after they began to smoke,"says Dr. Chaiton.
_________(57)
A:groups
B:sets
C:species
D:versions
共用题干
Germs（细菌）on Banknotes
People in different countries use different types of money:yuan in China,pesos in Mexico,pounds in the United Kingdom,dollars in the United States,Australia and New Zeal-and. They may use different currencies,but these countries,and probably all countries,still have one thing in______(1):germs on the banknotes.
Scientists have been studying the germs on money for well over 100 years. At the turn of the 20th______(2),some researchers began to suspect that germs living on money could spread disease.
Most studies of germy money have looked at the germs on the currency______(3)one country. In a new study,Frank Vriesekoop and other researchers compared the germ populations found on bills of different______(4).
Vriesekoop is a microbiologist at the University of Ballarat in Australia. He led the stud-y,which compared the germ populations found on money______(5)from 10 nations. The scientists studied 1,280 banknotes in total;all came from places where people buy food,like supermarkets,street vendors and cafes,______(6)those businesses often rely on cash.
Overall,the Australian dollars hosted the fewest live bacteria一no more than 10 per square centimeter. Chinese yuan had the______(7）about 100 per square centimeter. Most of the germs on money probably would not cause harm.
What we call“paper money”_________(8)isn't made from paper. The U. S. dollar,for ex- ample,is printed on fabric that is mostly cotton. Different countries may use different______(9)to print their money. Some of the currencies studied by Vriesekoop and his team,such as the American dollar,were made from cotton. Others were made from polymers.
The three______(10)with the lowest numbers of bacteria were all printed on poly-mers. They included the Australian dollar,the New Zealand dollar and some Mexican pesos.
The______(11)currencies were printed on fabric made mostly of cotton. Fewer germs lived on the polymer notes. This______(12)suggests that germs have a harder time staying alive on polymer surfaces. Scientists need to do more studies to understand______(13)germs live on, mon-ey—and whether or not we need to be concerned. Vriesekoop is now starting a study that will______(14)the amounts of time bacteria can stay alive on different types of bills.
Whatever Vriesekoop finds,the fact remains:Paper money______(15)germs. We should wash our hands after touching it;After all,you never know where your money's been. Or what's living on it.
6._________
A: because
B: though
C: so
D: when
共用题干
第一篇
Walking to Exercise the Brain
Do you think sitting and studying all the time will improve your grades?Think again.Getting some exer-
cise may help,too.
New research with old people suggests that taking regular walks helps them pay attention better than if
they didn't exercise.
Previous research had shown that mice learn,remember,and pay attention better after a few weeks of
working out on a running wheel.Mice that exercise have greater blood flow to the brain than those who don't.
Their brain cells also make more connections.
Neuroscientists（神经科学家）from the University of Illinois at Urbana Champaign wanted to find out if
the same thing is true for people.First,they measured the physical fitness of 41 adults,ages 58 to 77,after
each person walked 1 mile.Then,participants looked at arrows on a computer screen and had to use computer
keys to show which way one particular arrow was pointing.
Adults who were physically fit were faster at the arrow task,and their answers were just as accurate as
their less-fit peers,the researchers found.The fitter participants also had more blood flow to a part of their
brain responsible for paying attention and making decisions.
In a second study , 15 elderly people who completed a 6-month aerobic-training（有氧运动）course were
faster at attention tasks compared with 14 seniors who just did stretching and toning exercises（韵律操）for
the same amount of time.
So,even going for a walk every 2 or 3 days for just 10 to 45 minutes can help.That should be good news
for the elderly.
The effects of exercising on the brains of younger people haven't been studied yet. Still,it can't hurt to
take occasional breaks and go for a walk or run around with friends.Whatever you do,though,don't try to
read and walk at the same time.You could end up hurting yourself!
The first study on 41 elderly people found______________.
A:the less-fit participants did arrow tasks faster
B:the fitter participants did arrow tasks faster
C:the less-fit participants gave more accurate answers
D:the fitter participants gave more accurate answers
共用题干
Where Has the Salt Come from?
Every now and then,we meet a fact about our earth that makes us feel strange and no
answer for the fact has yet been found.Such a fact is the existence of salt in the oceans.
How did it get there?
We simply do not know how the salt got into the ocean!We do know,of course,that
salt is water-soluble,and so passes into the oceans with rainwater.The salt of the earth's
surface is constantly being dissolved（溶解）and is passing into the ocean.
But we do not know whether this can explain the huge quantity of salt in oceans.If all
the oceans were dried up,enough salt would be left to build a wall 180 miles high and a
mile thick. Such a wall would reach once around the world at the Equator（赤道）!
The common salt that we all use is produced from seawater or the water of salt lakes,
from salt springs（源泉）and from deposits of rock salt. The concentration（浓度）of salt in
seawater ranges from about three percent to three-and-one-half percent. The Dead Sea,
which covers an area of about 340 square miles,contains about 11,600,000,000 tons of
salt!
On the average, a gallon（加仑）of seawater contains about a quarter of a pound of
salt.The beds of rock salt that are found in various parts of the world were all originally
formed by the evaporation（蒸发）of seawater millions of years ago. It is believed that the
thick rock-salt deposits were formed after about nine-tenth of theY volume of seawater had
been evaporated.
Most commercial salt is obtained from rock salt.The usual method is to drill wells（井）
down to the salt beds. Pure water is pumped down（抽进去）through a pipe. The water
dissolves the salt and it is forced through another pipe up to the surface.
We have not fully understood how salt got into the ocean.
A:Right
B:Wrong
C:Not mentioned
