相关试题
共用题干
第二篇
Some People do Not Taste Salt Like Others
Low-salt foods may be harder for some people to like than others,according to a study by a Penn State
College of Agricultural Sciences food scientist.The research indicates that genetic factors influence some of
the difference in the levels of salt we like to eat.
Those conclusions are important because recent,well-publicized efforts to reduce the salt content in food
have left many people struggling to accept fare that simply does not taste as good to them as it does to others,
pointed out John Hayes,assistant professor of food science who was lead investigator on the study.
Diets high in salt can increase the risk of high blood pressure and stroke.That is why public health ex-
perts and food companies are working together on ways to help consumers lower salt intake through foods that
are enjoyable to eat.This study increases undersfanding of salt preference and consumption.
The research involved 87 carefully screened participants who sampled salty foods such as soup and
chips,on multiple occasions,spread out over weeks.Test subjects were 45 men and 42 women,reportedly
healthy,ranging in age from 20 to 40 years.The sample was composed of individuals who were not actively
modifying their dietary intake and did not smoke cigarettes.They rated the intensity of taste on a commonly
used scientific scale,ranging from barely detectable to strongest sensation of any kind.
"Most of us like the taste of salt.However,some individuals eat more salt,both because they like the
taste of saltiness more,and also because it is needed to block other unpleasant tastes in food,"said Hayes.
"Supertasters,people who experience tastes more intensely,consume more salt than nontasters do.Snack
foods have saltiness as their primary flavor,and at least for these foods,more is better,so the supertasters
seem to like them more."
However,supertasters also need higher levels of salt to block unpleasant bitter tastes in food such as
cheese,Hayes noted."For example,cheese is a wonderful blend of dairy flavors from fermented milk,but al-
so bitter tastes from ripening that are blocked by salt,"he said."A supertaster finds low-salt cheese unpleasant
because the bitterness is too pronounced."
Hayes cited research done more than 75 years ago by a chemist named Fox and a geneticist named
Blakeslee,showing that individuals differ in their ability to taste certain chemicals.As a result,Hayes ex-
plained,we know that a wide range in taste acuity exists,and this variation is as normal as variations in eye
and hair color.
"Some people,called supertasters,'describe bitter compounds as being extremely bitter,while others,
called nontasters,find these same bitter compounds to be tasteless or only weakly bitter,"he said."Response
to bitter compounds is one of many ways to identify biological differences in food preference because super-
tasting is not limited to bitterness."
It is true that_________.
A:nontasters like to share salty cheese with supertasters
B:nontasters consume more salt because they like intense tastes
C:supertasters like the taste of saltiness to block sweet tastes in food
D:supertasters like snack foods more as they contain higher levels of saltiness
共用题干
The Greatest Mystery of Whales
The whale is a warm-blooded,air-breathing animal,giving birth to its young alive,sucking them-and, like all mammals,originated on land.There are many______(51)of this.Its front flippers（鳍状肢）, used for steering and stability,are traces of feet.
Immense strength is______(52)into the great body of the big whales,and in fact most of a wha'e'sbo衡is one gigantic muscle.The blue whale's pulling strength has been estimated______(53) 400 horsepower.One specimen was reported to have towed（拖）a whaling vessel for seven hours at the______ (54)of eight knot（节）.
An angry whale will______(55).A famous example of this was the fate of Whaler Essex,______(56)was sunk off the coast of South America early in the last century.More recently,steel ships
have ___________( 57 ) their plates buckled（使弯曲）in the same way.Sperm whales（抹香鲸）were known to seize the old-time whaleboats in their jaws and crush them.
The greatest______(58)of whales is their diving ability.The sperm whale dives to the bottom for his ______(59)food,the octopus（章鱼）.In that search he is known to go as far down as 3,200 feet,where the ______(60)is 1 ,400 pounds to a square inch.Doing so he will______(61)underwater as long as one hour.Two special1 skills are involved in this storing up enough______(62)(all whales are air-breathed ) and tolerating the great change in pressure.Just how he does it scientists have not______(63).It is believed that some of the oxygen is stored in a special______(64)of blood vessels,rather than just held in the lungs.And it is believed that a special kind of oil in his head is some sort of a compensating mechanism that ______(65)adjusts the internal pressure of his body.But since you can't bring a live whale into the laboratory for study,no one knows just how these things work.
65._________
A:mentally
B:artificially
C:manually
D:automatically
共用题干
Earth Rocks on
Most of the time,the ground feels solid beneath our feet. That{S comforting. But it's also misleading
because there's actually a lot going on underground.Masses of land(called plates)slip,slide,and bump
against each other,slowly changing the shape of continents and oceans over millions and billions of years.
Scientists know that Earth formed about 4.5 billion years ago.They also know that our planet was hot at
first. As it cooled , its outermost layer , called the crust（地壳）, eventually formed moving plates. Exactly
when this shift happened,however,is an open question.
Now,an international group of researchers has an answer. They'ye found new evidence suggesting that
Earth's crust started shifting at least 3.8 billion years ago.The new estimate is 1.3 billion years earlier than
previous ones.
Not long before 3. 8 billion years ago,lots of asteroids（小行星）were hitting Earth,keeping its crust in
a hot,melted state.After the hard crust formed,much of it sank at various times into the planet's hot in-
sides.There,it melted before returning to the surface.
In some places,however,the crust never sank.One of the oldest such places is in Greenland,in an area
called the Isua supracrustal（上地壳） belt. The rocky crust there is between 3. 7 and 3. 8 billion years old.
The belt was once part of the seafloor,but now it is exposed to air.
The researchers recently took a close look at the Isua supracrustal belt. They noticed long,parallel
cracks in the rock that have been filled in with a type of volcanic rock.
To explain this structure,the scientists propose that tension in the crust caused the seafloor to crack
open long ago. Hot , liquid rock , called magma（岩浆）,flowed up slowly from deep inside Earth to fill the
cracks.Finally,the whole area cooled,forming what we see today.
That explanation,plus chemical clues inside the rock,suggests that the Isua supracrustal belt was once
part of a plate under the ocean,beginning around 3.8 billion years ago.
The shape of lands and oceans are slowly changed with the movements of plates.
A:Right
B:Wrong
C:Not mentioned
共用题干
The iPad
1 The iPad is a tablet computer（平板电脑）designed and developed by Apple. It is particularly mar-
keted as a platform for audio and visual media such as books,periodicals,movies,music,and games,as well
as web content.At about 1.5 pounds(680 grams),its size and weight are between those of most contempora-
ry smartphones and laptop computers.Apple released the iPad in April 2010,and sold 3 million of the de-
vices in 80 days.
2 The iPad runs the same operating system as iPod Touch and iPhone.It can run its own applications
as well as ones developed for iPhone.Without modification,it will only run programs approved by Apple and
distributed via its online store.
3 Like iPhone and iPod Touch,the iPad is controlled by a multitouch display一a break from most pre-
vious tablet computers , which uses a pressure-triggered stylus（触控笔）.The iPad uses a Wi-Fi data connec-
tion to browse（浏览）the Internet, load and stream media ,and install software. Some models also have a 3G
wireless data connection which can connect to GSM 3 G data networks.The device is managed and synchro-
nized by iTunes on a personal computer via USB cable.
4 An iPad has different features and applications one can use to execute different and interesting
things.There are lots of iPad applications that the owner can use to enhance the way they communicate.Some
of these are how to use social networking sites and other online options.One of the most common uses is for
e-mail services.iPad applications like Markdown Mail allow the adoption of specific and particular options.
They enable the owner to personalize their email accounts.
5 While the iPad is mostly used by consumers it also has been taken up by business users.Some com-
panies are adopting iPads in their business offices by distributing or making available iPads to employees.Ex-
amples of uses in the workplace include lawyers responding to clients,medical professionals accessing health
records during patient exams,and managers approving employee requests.A survey by Frost&Sullivan shows
that iPad usage in workplaces is linked to the goals of increased employee productivity,reduced paperwork,
and increased revenue.
In April 2010 the iPad developed by Apple was_____.
A:distributed
B:personalized
C:modified
D:increased
E:browsed
F:released
When I heard the noise in the next room,I couldn't resist having a peep.
A: chance
B: visit
C: try
D: look
