加载中…2017年6月北美SAT真题
(2017-11-02 10:14:49)
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sat真题美国大学 |
分类： 新SAT真题下载/回顾 |
http://s13/mw690/001K3Dbwzy7fuaDzhSs8c&690
1. 小说
Literature：
内容：小女孩的姑母要来找她，被小女孩父亲拒绝的故事。
2. 自然科学
Science：
一篇讲述恐龙灭绝
参考内容：
Updated:
Drilling of dinosaur-killing impact crater explains buried circular
hills
UPDATE:
Today, scientists published their first results from a drilling
expedition into Chicxulub crater, the buried remnants of an
asteroid impact off the Yucatán Peninsula in Mexico that killed off
the dinosaurs 66 million years ago. Their discovery of shocked,
granite rocks from deep in the crust placed “out of order” on top
of sedimentary rocks validates the dynamic collapse theory of
formation for Chicxulub’s peak ring, the scientists says. Chicxulub
is the only well-preserved crater on Earth with a peak ring, but
they abound elsewhere in the inner solar system. Last month,
scientists using instruments on a NASA lunar mission showed that
the peak rings within the Orientale impact basin were likely to
have formed in a similar way as at
Chicxulub.
Here is our original story:
Scientists have reached ground zero for one of the world’s
most famous cataclysms. Burrowing into the impact structure
responsible for the demise of the dinosaurs, a team of researchers
has achieved one of its main goals, with rocks brought up from 670
meters beneath the sea floor off the coast of the Yucatán
Peninsula. These core samples contain bits of the original granite
bedrock that was the unlucky target of cosmic wrath 66 million
years ago, when a large asteroid struck Earth, blasted open the
180-kilometer-wide Chicxulub crater, and led to the extinction of
most life on the planet.
“We’re
feeling pretty good,” said co–chief scientist Sean Gulick in an
interview from the deck of a drilling platform 30 kilometers
offshore in the Gulf of Mexico. “I’m not getting much sleep out
here, so we’re a little delirious.”
Although
scientists have drilled into the buried crater before on land, this
is the first offshore effort, and also the first to go after the
crater’s “peak ring”—a circular ridge inside the crater rim that’s
characteristic of the solar system’s largest impact craters.
Astronomers see peak rings on the moon, Mars, and Mercury, but they
have never been able to sample one on Earth until now. The team has
already been charting the return of life after the worldwide
die-off in cores from higher up in the hole. By examining peak ring
rocks closely, they hope to test models of crater formation and
determine whether the crater itself was one of the first habitats
for microbial life after the impact.
The peak ring
formed in a matter of minutes. Just after the impact, deep granite
bedrock, flowing like a liquid, rebounded into a central tower as
tall as 10 kilometers before collapsing into the circular ridge.
Next, the peak ring was covered by a layer of jumbled-up rocks,
called a breccia, that contains chunks of blasted-up rock and
impact melt. Then, in the hours that followed, ocean tsunamis
dumped huge amounts of sandy sediment in the giant hole in Earth.
Further deposition would come slowly, as life returned to the seas,
and layers of limestone were built up in the ensuing millions of
years.
Last week,
researchers brought up a 3-meter core section from a depth of 670
meters that contained bits of granite along with minerals
originally deposited in hot, fluid-filled cracks—the first sign
that the team had entered the peak ring. “We predicted the peak
ring would be a big hydrothermal system,” says Gulick, a
geophysicist at the University of Texas, Austin. He says it may be
several more days of drilling before granite dominates the core
samples and the team can declare itself entirely within the peak
ring. However, Joanna Morgan, the other chief scientist at Imperial
College London, thinks the presence of any granite at all signifies
that the team is now working within the peak ring layer. “How far
down into the peak ring is the peak ring?” Gulick asks. “It’s
almost a semantic argument.”
Another bone
of contention for the team concerns the boundary between the
Cretaceous—the last age of the dinosaurs—and the Paleogene, the
period that began 66 million years ago. Traditionally, Morgan says,
the K-Pg boundary, as it is known, has been defined by appearance
of fossils of small shelled creatures called foraminifera. By that
definition, the team crossed the K-Pg boundary last week, at a
depth of 620 meters, when drillers left fossil-containing limestone
layers and entered sandy tsunami deposits. But Gulick points out
that the tsunami deposits and impact breccia found between 620 and
670 meters all came after the impact itself, so they could
technically be considered part of the Paleogene. He suggests that
scientists instead call this thick section between the Cretaceous
and Paleogene an “event layer.”
The team of
scientists living on board the drilling platform is now
investigating the fractures and veins of minerals that precipitated
out of hot solutions in the wake of the impact. Some of the
minerals they’ve found suggest that, initially at least, the
fluid-filled cracks were way too hot for life. But they are hoping
to find signs of ancient and modern DNA. As hellish as the impact
was, the team suspects that the buried peak ring itself may have
been an early place for life to return, because of the nutrients in
the hot fluid-filled fractures.
As of 1 May,
the team has reached a depth of 700 meters. It is funded to drill
through the first week of June, and hopes to go as deep as 1500
meters. As the researchers move deeper into the harder granites of
the peak ring, they will core more slowly, obtaining a 3-meter core
about every 2 hours. They will look for evidence that the peak ring
rocks are flipped “out of order,” with deeper rocks lying on top of
rocks that originally sat more shallowly and contain minerals with
higher levels of shocking. This would confirm one of the main
models for peak ring formation.
The drilling
effort began at the beginning of April and is sponsored by the
International Ocean Discovery Program (IODP). To avoid choppy ocean
waters, the scientists are using a special vessel called a lift
boat that has jacked itself up off the sea floor on three pylons.
Morgan, who just arrived on the drilling platform over the weekend,
says the mission is the culmination of years of effort that began
with her first proposal to IODP in 1998. “I had this dream we would
drill this impact crater many years ago,” she says. “To see this
immense structure and all the people here, it’s been really
amazing.”
一篇关于水的浮力。
参考内容：
Repulsive
quantum effect finally measured
A quantum
effect that causes objects to repel one another – first predicted
almost 50 years ago – has at last been seen in the
lab.
According to Harvard physicist Federico Capasso, a member of
the group who measured the effect, it could be used to lubricate
future nanomachines.
The team detected the weak repulsive force when they brought
together a thin sheet of silica and a small gold-plated bead, about
half the diameter of a human hair.
The force is an example of the Casimir effect, generated by
all-pervasive quantum fluctuations.
Strange attraction
The simplest way to imagine the Casimir force in action is to
place two parallel metal plates in a vacuum. Thanks to the odd
quantum phenomenon, these become attracted to one another.
It happens because even a vacuum is actually fizzing with a
quantum field of particles, constantly popping in and out of
existence. They can even fleetingly interact with and push on the
plates.
However, the small space between the two plates restricts the
kind of particles that can appear, so the pressure from behind the
plates overwhelms that from between them. The result is an
attractive force that gums up nanoscale machines. (To learn more
about the Casimir force see Under pressure from quantum
foam.)
Capasso says that the Casimir force needn’t be an enemy.
“Micromechanics at some point will have to contend with these
forces – or make use of them.”
Reverse buoyancy
In 1961, Russian theorists calculated that in certain
circumstances, the Casimir effect could cause objects to repel one
another – a scenario Capasso’s team have finally created
experimentally. The team achieved this by adding a fluid,
bromobenzene, to the setup.
The Casimir attraction between the liquid and the silica plate
is stronger than that between the gold bead and the silica, so the
fluid forces its way around the bead, pushing it away from the
plate.
The effect is akin to the buoyancy we experience in the macro
world – where objects less dense than water are held up by the
liquid around them. But in this case the bromobenzene is less dense
than the solid bead. “You could call it quantum buoyancy,” Capasso
told New Scientist.
The force he measured was feeble – amounting to just a few
tens of piconewtons – but that is still enough to buoy up nanoscale
objects.
Quantum bearings
“The next experiment we want to do is use a TV camera to track
the motion of one of these spheres, then we should be able to see
easily whether you have levitation.”
Harnessing the repulsive Casimir force could provide a kind of
lubrication to solve the problem of nanomachines becoming gummed up
by the better-known attractive version, says Capasso.
In theory you could instead use a liquid denser than the
components to buoy them up, but that wouldn’t be practical. “These
gizmos are usually made of metal, so you would have to use
mercury,” he explains.
Quantum buoyancy bearings could be used to build delicate
sensors, such as a floating “nanocompass” to detect small-scale
magnetic fields.
3. 社会科学 Social
Science
Public volunteer vs. private
volunteer
公共义工与独立组织义工
参考内容：
Non-profit organizations
typically fall into one of two categories: public and private.
While a public non-profit organization receives the majority of its
funding from the general public, a private non-profit organization
receives most of its funds from only a few private sources, such as
through donations from a single family or
corporation.
About
Non-Profits
A non-profit
organization is a company created for purposes other than earning a
profit. Typical non-profit organizations include hospitals,
schools, churches, political organizations, public clinics, labor
unions, volunteer organizations, museums, research institutes,
professional associations and legal aid societies. Most non-profit
organizations enjoy tax exemption from the federal government if
they exist for the purpose of charity, religion, public safety,
science, education, literacy, the development of sports or the
prevention of cruelty to animals or children.
Public
Non-Profits
Public non-profit
organizations obtain most or all of their financial support through
donations they receive from the general public. Some of these
organizations, such as those that provide services or goods to the
needy, may procure funding by holding fundraisers in which they
collect small donations from individuals who sympathize with their
purpose. Other public non-profits, such as museums, may raise money
by offering certain perks in exchange for paid memberships.
Private
Non-Profits
Private
non-profit organizations receive financial support from only a few
sources, such as a dedicated donor or investment income. In some
cases, a private non-profit organization may receive a large
portion of its funding from the individual who founded the
organization. Founders of private non-profit organizations may
secure additional funding from other wealthy donors who are
interested in furthering the same cause. Private non-profit
organizations typically don't solicit funds from the general
public.
Considerations
Some public
non-profit organizations may receive goods from the public rather
than monetary donations. Some states exempt non-profit
organizations from tort liability and from paying unemployment
insurance taxes, regardless of whether the organization is
receiving public or private funding. All federally recognized
non-profit organizations are exempt from paying Social Security
taxes, but some organizations elect to pay them
anyway.
4. 历史文献
形式：美国历史文献考察了长对比，继续保持互怼态度。
内容：汉密尔顿怼保皇派，关于北美是否要脱离英国统治。
本次考试CB至少起用了3套题目。仅历史文献，就有三个话题(三套题目)：
(1)独立运动话题：汉密尔顿 vs
保皇派;长双;北美是否应该独立;
(2)女权话题：女性平等权;长双;一篇通过一个议案，希望女性平权;一篇认为，法律已经保护了女性权利，不必须和男性平权;
(3)女权话题：与美国女诗人 艾米莉 狄金森(Emily
Dickinson)相关(具体内容待确定);
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