_____
　　
A.For example, the people in men's dreams are often other men, and the dreams often involve fighting.
　　B.Men and women dream about different things.
　　C.A criminal, for example, might dream about crime.
　　D.However, one thing they agree on this: If you dream that something terrible is going to occur, you shouldn't panic.
　　E.It was only in the twentieth century that people started to study dreams in a scientific way.
　　F.He thought people could learn more about themselves by thinking about their dreams.

共用题干
第一篇
Putting Plants to Work
Using the power of the sun is nothing new.People have had solar-powered calculators and buildings with
solar panels（太阳能电池板）for decades. But plants are the real experts. They' ve been using sunlight as an
energy source for billions of years.
Cells in the green leaves of plants work like tiny factories to convert sunlight, carbon dioxide（二氧化
碳）,and water into sugars
and starche（淀粉）,stored energy that the piants can use. This conversion
process is called photosynthesis (光合作用）Unfortunately, unless you' re a plant, it's difficult and
expensive to convert sunlight into storable energy. That's why scientists are taking a closer look at exactly
how plants do it.
Some scientists are trying to get plants,or biological cells that act like plants, to work as very small
photosynthesic power stations. For example, Maria Ghirardi of the National Renewable Energy Laboratory in
Golden. Cobo.,is working with green algae（水藻）.She's trying to trick them into producing hydrogen
instead of sugars when they perform photosynthesis. Once the researchers can get the algae working efficient-
ly ,the hydrogen that they produce could be used to power fuel cells in cars or to generate electricity.
The algae are grown in narrow-necked glass bottles to produce hydrogen in the lab. During photosynthe-
sis , plants normally make sugars or strchds. "But under certain conditions,a lot of algae are able to use the
sunlight energy not to store starch , but to make hydrogen."Ghirardi says. For example ,algae will produce hy-
drogen in an airfree environment. It' s the oxygen in the air that prevents algae from making hydrogen most of
the time.
Working in an airfree environment, however, is difficult. It's not a practical way to produce cheap
energy. But Ghirardi and her colleagues have discovered that by removing a chemical called sulfate（硫酸盐）
from the environment that the algae grow in, they will make hydrogen instead of sugars,even when air
is present.
Unfortunately, removing the sulfate also makes the algae's cells work very slowly,and not much
hydrogen is produced. Still ,the researchers see this as a first step in their goal to produce hydrogen efficiently
from algae. With more work,they may be able to speed the cells' activity and produce larger quantities
of hydrogen.
The researchers hope that algae will one day be an easy-to-use fuel source. The organisms are cheap to
get and to feed, Ghirardi says,and they can grow almost anywhere:"You can grow them in a reactor, in a
pond. You can grow them in the ocean. There's a lot of flexibility in how you can use these organisms."
Scientists study how photosynthesis works because they want to_______________.
A: improve the efficiency of it
B: turn plant sugars to a new form of energy
C: get more sugars and starches from plants
D: make green plants a new source of energy

The river widens considerably as it begins to turn west.
A:extends
B:stretches
C:broadens
D:bends

共用题干
Eastern Quakes can Trigger Big Shakes
In the first week of November 2011,people in central Oklahoma experienced more than two dozen earth-
quakes.The largest,a magnitude（量）5.6 quake,shook thousands of fans in a college football stadium,
caused cracks in a few buildings and scared many people who had never felt a quake before.Oklahoma is not
an area of the country famous for its quakes.If you watch the news on TV,you will see reports about all sorts
of natural disasters.But the most dangerous type of natural disaster,and also the most unpredictable,is the
earthquake.
Researchers at the US Geological Survey(USGS)estimate that several million earthquakes occur globally
each year. That may sound scary,but people don't feel many of them because they happen in remote and
unpopulated regions.Many quakes happen under the ocean,and others have a very small magnitude.
Scientists know about small,remote quakes only because of very sensitive electronic devices called seis-
mometers（地震仪）.These devices detect and measure the size of ground vibrations（震颤）produced by
earthquakes.Altogether,USGS researchers use seismometers to identify and locate about 20,000 earthquakes
each year.
Although earthquakes can happen anywhere in the world,really big quakes occur only in certain areas.
The largest ones register a magnitude 8 or higher and happen,on average,only once each year. Such big
ones typically occur along the edges of Earth ' s tectonic plates（构造板块）.
Tectonic plates are huge pieces of Earth ' s crust（外壳）,sometimes many kilometers thick. Often,
edges of these plates temporarily lock together. When plates push and scrape（擦）past each other earthquakes
occur. On average,tectonic plates move very slowly一about the same speed as your fingernails grow.
But sometimes earthquakes rumble（轰轰作响）through portions of the landscape far from a plate ' s
edges.Although less expected,these"mid-plate"small earthquakes can do substantial damage.Some of the
biggest known examples hit the eastern half of the United States two centuries ago.Today,scientists are still
puzzling over why the quakes occurred and when similar ones might occur.
The earthquake is the most unpredictable natural disaster.
A:Right
B:Wrong
C:Not mentioned

共用题干
Climate Change Poses Major Risks for Unprepared Cities
A new examination of urban policies has been carried out recently by Patricia Romero Lankao. She is a so-
ciologist specializing in climate change and_____________(51) development. She warns that many of the world'5
fast-growing urban areas,especially in developing countries,will likely suffer from the_____________(52)of
changing climate. Her work also concludes that most cities are failing to_____________(53)emissions of carbon
dioxide and other greenhouse gases. These gases are known to affect the atmosphere.
"Climate change is a deeply local issue and poses profound_____________ (54) to the growing cities of the
world,"says Romero Lankao. "But too few cities are developing effective strategies to protect their residents."
Cities are_____________(55)sources of greenhouse gases.And urban populations are likely to be among
those most severely affected by future climate change.Lankao's findings highlight ways in which city-resi-
dents are particularly vulnerable,and suggest policy interventions that could offer immediate and longer-term
____________ (56).
The locations and dense construction patterns of cities often place their populations at greater
_____________(57)for natural disasters.Potential threats associated with climate include storm surges and pro-
longed hot weather. Storm surges can flood coastal areas and prolonged hot weather can heat_____________(58)
paved cities more than surrounding areas. The impacts of such natural events can be more_____________(59)in
an urban environment. For example,a prolonged heat wave can increase existing levels of air pollution,causing
widespread health problems.Poorer neighborhoods that may_____________(60)basic facilities such as drinking
water or a dependable network of roads,are especially vulnerable to natural disasters.Many residents in
poorer countries live in substandard housing_____________(61)access to reliable drinking water,roads and
basic services.
Local governments,therefore,should take measures to_____________(62)their residents."Unfortunately,
they tend to move towards rhetoric_____________(63)meaningful responses,"Romero Lankao writes,"They don't
impose construction standards that could reduce heating and air conditioning_____________(64).They don't em-
phasize mass transit and reduce automobile use.In fact,many local governments are taking a hands-off ap-
proach."_____________(65),she urges them to change their idle policies and to take strong steps to prevent
the harmful effects of climate change on cities.
_________(54)
A:threats
B:interests
C:implications
D:differences

A peculiarly pointed chin is his most memorable facial characteristic.
A:mark
B:feature
C:trace
D:appearance