[单项选择]According to the passage, why do ants use different compounds as trail pheromones
A. ( To reduce their sensitivity to some chemicals
B. ( To attract different types of ants
C. ( To protect their trail from other species
D. ( To indicate how far away the food is

[单项选择]According to the passage, the fundamental difference between the natural sciences and the social sciences is that ______.
A. the social sciences are primarily concerned with the behavior of material things whereas the natural sciences mainly deal with the behavior of men
B. the natural scientist does not care how his subject matter behaves while the social scientist is interested in the behavior of his subject matter
C. the social sciences deal with the behavior of men whereas the natural sciences deal with the behavior of material things
D. men are always subjective and emotional whereas the nature is objective and unemotional

[单项选择]According to this passage, why do most companies employ thin people to promote their products
A. Because thin people eat less and therefore ask for less pay.
B. Because thin people lend to be more hardworking than fat people.
C. Because thin people are considered vigorous, youthful and more likely to succeed.
D. Because thin people are more willing to work for big companies.

[单项选择]

Passage 3 Why do so many Americans distrust what they read in their newspapers The American Society of Newspaper Editors is trying to answer this painful question. The organization is deep into a long self - analysis known as the journalism credibility project. Sad to say, this project has turned out to be mostly low - level findings about factual errors and spelling and grammar mistakes, combined with lots of head -scratching puzzlement about what in the world those readers really want. But the sources of distrust go way deeper. Most journalists learn to see the world through a set of standard templates (patterns) into which they plug each day’s events. In other words, there is a conventional story line in the newsroom culture that provides a backbone and a ready - made narrative structure for otherwise confusing news. There exists a social and cultural disconnect between journalists and their readers, which helps explain why the "standard templates" of th
A. Needs of the readers all over the world.
B. Causes of the public disappointment about newspapers.
C. Origins of the declining newspaper industry.
D. Aims of a journalism credibility project.

[单项选择]According to the passage, why do workers want more money
A. Because their jobs are too boring.
B. Because they want to enjoy more spare time.
C. Because they want to make their jobs more interesting.
D. Because they demand shorter working hours.

[单项选择]According to the passage, why do people buy tickets to a concert

[单项选择]According to the passage, why do we have futures contracts
A. To take delivery of a given commodity.
B. To make the market against price fluctuations stable.
C. To ensure delivery of a given commodity at market prices.
D. To allow for some price certainty before a commodity is delivered.

[单项选择]According to the passage, why some scientists are thinking twice about doing or reporting their research
A. Because they are lack of fund.
B. Because they have to share the honor with others.
C. Because their research may arouse Controversy.
D. Because the government bans them from publishing the results of their research.

[单项选择]According to the passage, why is plankton considered to be more valuable than land grasses
A. It is easier to cultivate.
B. It produces move carbohydrates.
C. It does not require soil.
D. It is more palatable.

[单项选择]According to the passage, why has human intelligence not been copied in the making of a robot
A. Computers can only do mathematical problems better than human beings.
B. Technology is not advanced enough to copy how human minds work.
C. Scientists are satisfied to have the robot with senses of sight and touch.
D. Robots with human intelligence will be dangerous to human beings.

[单项选择]According to the passage, why did colonial printers avoid major publishing projects
A. Few colonial printers owned printing machinery tha was large enough to handle major projects
B. ( There was inadequate shipping available in the colonies
C. ( Colonial printers could not sell their work for a competitive price
D. ( Colonial printers did not have the skills necessary to undertake large publishing projects

[单项选择]According to the passage, why are handwritten documents hard of access on the web
A. The amount of such documents is huge and hard to read.
B. Handwriting differs greatly from person to person.
C. Handwritings have never got definite digital counterparts.
D. Less people are willing to read handwritings today.

[单项选择]According to the passage, why is magnesium important to industry
A. It is strong.
B. It conducts heat well.
C. It weighs little.
D. It is inexpensive to produce.

[单项选择]According to the passage, why has general knowledge of botany begun to fade
A. People no longer value plants as a useful resource.
B. Botany is not recognized as special branch of science.
C. Research is unable to keep up with the increasing numbers of plants.
D. Direct contact with a variety of plants has decreased.