更多"Scientists have been unable to ____"的相关试题:
[单项选择]Scientists have been trying to come up with biological explanations for the difference between boys and girls.
A. 科学家们已经努力提出用生物学来解释男孩与女孩间的这种并异。
B. 科学家们已经试图把男生与女生之间的差异用生物来解释。
C. 科学们一直试图从生物学的角度来解释男孩和女孩间的差异。
D. 科学家们已经试图提出男孩和女孩生理上的差异。
[单项选择]Scientists have been eager to ______ for research funds without thinking over the impact of the research.
A. scramble
B. tumble
C. bubble
D. couple
[单项选择]Some scientists think there may have been life on the Mars in the past because ______.
A. there is no life there now
B. there is a large amount of water at the poles
C. the Mars may be able to support life in the future
D. conditions may have been similar to those on the Earth
[单项选择]Many scientists have been {{U}}probing{{/U}} psychological problems.
A. solving
B. exploring
C. settling
D. handling
[单项选择]They have been trying to find out the identity of the writer of the________letter, but in vain.
A. infamous
B. autonomous
C. anonymous
D. unanimous
[单项选择]Scientists are trying to find a link between pollution and ______.
A. intelligence levels
B. antisocial behavior
C. birth defects
D. divorce percentage
[单项选择]______ a large number of students have been unable to find accommodations on campus this year.
A. Every
B. Quite
C. All
D. Both
[单项选择]Scientists wilt have to ______ new methods of increasing the world's food supply in order to feed more hungry people.
A. catch up with
B. come up with
C. keep up with
D. put up with
[单项选择]
Scientists have established that influenza viruses taken from man can cause the disease in animals. In addition, man can catch the disease from animals. In fact, a great number of wild birds seem to carry the virus without showing an evidence of illness. Some scientists concluded that a large family of influenza viruses may have evolved in the bird kingdom, a group that has been on the earth 100 million years and is able to carry the virus without contracting the disease. There is even convincing evidence to show that virus strains are transmitted from place to place and from continent to continent by migrating birds.
It’s known that two influenza viruses can recombine when both are present in an animal at the same time, the result of such recombination is a great variety of strains containing different H and N spikes. This raises the possibility that a human influenza virus can recombine with an influenza virus from a low animal to produce an entirely new s
A. A type of wild pig
B. diseased lower animals
C. a group of migrating birds
D. a variety of means
