Scientists say it may be ten years______this medicine was put to use.A.sinceB.beforeC.afte
Scientists say it may be ten years______this medicine was put to use.
A.since
B.before
C.after
D.when
Scientists say it may be ten years______this medicine was put to use.
A.since
B.before
C.after
D.when
Scientists say that many factors ______ changes in the weather.
A.bring in
B.bring off
C.bring about
D.bring forward
The article does not say whether the scientists' experiments with dogs have ______.
A.benefited animals other than dogs
B.served man
C.helped other dogs
D.contributed to medical knowledge
A.reduce
B.reduces
C.reduced
D.must reduce
A) since
B) before
C) after
D) when
What scientists can do right now is make good maps of fault zones and (7)_____ out which ones are probably due (8)_____ a rupture. And they can make forecasts. A forecast might say that, over a certain number of years, there is a certain (9)_____ of a certain magnitude earthquake in a (10)_____ spot. And that you should fix your house to its foundation and glue the water heater to the wall.
Turning forecasts into predictions—"a magnitude 7 earthquake is (11)_____ here three days from now"—may be impossible, but scientists are doing everything they can to solve the (12)_____ of earth quakes. They break rocks in laboratories, studying how stone (13)_____ under stress. They hike (14)_____ ghost forests where dead trees (15)_____ of long-ago tsunamis. They make maps of unsecured, balanced rocks to see where the ground has (16)_____ in the past and how hard. They dig ditches across faults, searching for the active trace. They have wired up fault zones with so many sensors it is (17)_____ the Earth is a patient (18)_____ intensive care.
(19)_____, we tell ourselves—trying hard to be persuasive—there must be some way to (20)_____ order and criterion on all that untrustworthy ground.
A.birth
B.rise
C.ground
D.way
Scientists are also trying to (11)_____ other scientists through Science and Nature, not just the public. The line between popular and professional notoriety is not (12)_____. Scientists tend to pay more attention to the Big Two than to other journals. (13)_____ more scientists know about a particular pa per, they are more apt to cite it in their own papers. Being often-cited will increase a scientist's "Impact Factor", a measure of how often papers are cited by (14)_____. Funding agencies use the Impact Factor as a (15)_____ measure of the influence of scientists they are considering supporting. (16)_____ Science and Nature papers have more visibility, the number of' submissions is growing, say the editors. Nature now gets 10,000 (17)_____ a year, and that figure is rising, says editor-in-chief Philip Campbell via email. In his opinion, this partly reflects the increase (18)_____ scientific activity around the word. It also (19)_____ reflects the increasing and sometimes (20)_____ emphasis amongst funding agencies and governments on publication measures, such as the typical rates of citation of journals.
A.even
B.though
C.although
D.as if
Asteroids are different forms of the meteoroids that race across the night sky. Most orbits the sun far from Earth and don't threaten us. But there are also thousands of asteroids whose orbits put them on a violent coming course together with Earth.
Buy $ 50 million worth of new telescopes right now. Then spend $10 mil]ion a year for the next 25 years to locate most of the space rocks. By the time we spot a fatal one, the scientists say, we'll have a way to change its course.
Some scientists favor pushing asteroids off course with nuclear weapons. But the cost wouldn't be cheap.
Is it worth it? Two things experts consider when judging any risk are: 1) How likely the event is; and 2) How bad the consequences if the event occurs. Experts think asteroids big enough to destroy lots of life might strike Earth once every 500,000 years. Sounds pretty rare but if one did fall it would be the end of the world. "If we don't take care of these big asteroids, they'll take care of us. "Says one scientist. "Its that simple."
The cure, though, might be worse than the disease, Do we really want fleets of nuclear weapons silting around on Earth? "The world has less to fear from doomsday rocks than from a great nuclear fleet set against them. "Said a New York Times article.
What does the passage say about asteroids and meteoroids?
A.They are heavenly bodies similar in nature.
B.There are more asteroids than meteoroids.
C.They are heavenly bodies different in composition.
D.Asteroids are more mysterious than meteoroids.
Of course,the best paper comes from wood.Wood comes from trees,and trees are plants.Vegetables and fruit and plants too,and we eat a lot of them.So can we also eat wood and paper?
Scientists say,"All food comes in some way from plants." Well,is that true? Animals eat grass and grow fat.Then we eat their meat.Little fish eat little sea-plants; then bigger fish swim along and eat the...Chickens eat bits of grass and give us...Think for a minute.What food does not come from plants in some way?
Scientists can do wonderful things with plants.They can make food just like meat and cheese.And they can make it without the help of animals.It is very good food too.Now they have begun to say,"We make our paper from wood.We can also make food from wood.The next thing is not very difficult." What is the next thing? Perhaps it is-food from paper.Scientists say,"We can turn paper into food.It will be good,cheap food too; cheaper than meat or fish or eggs."
So please keep your old books and letters.Don't feed them to your cat.) One day,soon,they will be on your plate.There is nothing like a good story for breakfast.
1、The best paper come from Wood.()
2、From the passage,we can infer 推断) thatfew kinds of food do not come from plants in some way.()
3、The main idea of the passage is all food comes from plants in some way.()
4、The writer asks us to keep our old books and letters because we can make food from them soon.()
5、The best title for the passage is " Food from Plants ".()
Scientists were embroiled (使卷入) last week in an international row over genetically modified cotton (GM cotton).
A study in China suggested for the first time that the crop was permanently damaging the environment and that insects were building up resistance to it.
The study, by the Nanjing institute of Environmental Science, combined the laboratory and field work from four Chinese scientific institutes. The study was done over a several - year period.
GM Cotton had a gene resistance to the cotton bollworm (棉铃虫) and isolated from the bacterium (细菌) named Bacillus thuringiensis (Bt), but the study found that it harms the natural parasitic (寄生的) enemies of the cotton bollworm.
It also indicated that populations of pests besides the bollworm had increased in Bt cotton fields and some had replaced the bollworm as the primary pest.
However, the leading GM company, the US's Monsanto, which controls more than 80 per cent of the Bt cotton grown worldwide, dismissed the research.
It said that the industry has always cited GM cotton as its biggest success, because it can increase yields by up to 60 per cent and reduce the need for pesticides (杀虫剂) by 80 per cent.
But, unfortunately for the industry, (80) the scientists also found that the resistance of Bt cotton to bollworm decreased significantly over time.
Why scientists say no to GM cotton?
A.Because the cotton was genetically modified.
B.Because the cotton was found to damage the environment.
C.Because the cotton harms the bollworm.
D.Because Monsanto dismissed the research.