听力原文：Of the students participating in our university's research project, 73% classified themselves as freshmen and sophomores.
（23)
A．Many university students prefer soft drinks to fresh fruits.
B．Most of them are first-or-second year college students.
C．A number of college students refuse to disclose their identities.
D．Not many students are interested in our research projects.

Gerald Feinberg, the Columbia University physicist, once went so far as to declare that "everything possible will eventually be accomplished." He didn't even think it would take very long for this to happen: "I am inclined to put two hundred years as an upper limit for the accomplishment of any possibility that we can imagine today."
Well, that of course left only the impossible as the one thing remaining for daring intellectual adventurers to whittle away at. Feinberg, for one, thought that they'd succeed even here. "Everything will be accomplished that does not violate known fundamental laws of science," he said, "as well as many things that do violate those laws."
So in no small numbers scientists tried to do the impossible. And how understandable this was. For what does the independent and inquiring mind hate more than being told that something just can't be done, pure and simple, by any agency at all, at any time, no matter what. Indeed, the whole concept of the impossible was something of an affront to creativity and advanced intelligence, which was why being told that something was impossible was an unparalleled stimulus for getting all sorts of people to try to accomplish it anyway, as witness all the attempts to build perpetual motion machines, antigravity generators, time-travel vehicles, and all the rest.
Besides, there was always the residual possibility that the naysayers would turn out to be wrong and the yeasayers right, and that one day the latter would reappear to laugh in your face. As one cryonicist pat it, "When you die, you're dead. When I die, I might come back. So who's the dummy？"
It was a point worth considering. How many times in the past had certain things been said to be impossible, only to have it turn out shortly thereafter that the item in question had already been done or soon would be. What greater cliche was there in the history of science than the comic litany of false it-couldn't-be-dones; the infamous case of Auguste Comte saying in 1844 that it would never be known what the stars were made of, followed in a few years by the spectroscope being applied to starlight to reveal the stars' chemical composition; or the case of Lord Rutherford, the man who discovered the structure of the atom, saying in 1933 that dreams of controlled nuclear fission were "moonshine".
And those weren't even the worst examples. No, the huffiest of all it-couldn't-be-done claims centered on the notion that human beings could actually fly, either at all, or across long distances, or to the moon, the stars, or wherever else. It was as if for unstated reasons human flight was something that couldn't be allowed to happen. "The demonstration that no possible combination of known substances, known forms of machinery and known forms of force, can be united in a practical machine by which man shall fly long distances through the air, seems to the writer as complete as it is possible for the demonstration of any physical fact to be." That was Simon Newcomb, the Johns Hopkins University mathematician and astronomer in 1906, three years after the Wright brothers actually flew.
There had been so many embarrassments of this type that about mid-century Arthur C. Clarke came out with a guideline for avoiding them, which he termed Clarke's Law: "When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong."
Still, one had to admit there were lots of things left that were really and truly impossible, even if it took some ingenuity in coming up with a proper list of examples. Such as: "A camel cannot pass through the eye of a needle." （Well, unless of course it was a very large needle.) Or: "It is impossible for a door to be simultaneously open and closed." （Well, unless of course it was a revolving door.)
Indeed, watertight examples of the
A．Science works by great leaps, not little steps.
B．Scientists will work harder than they do today.
C．Scientists' kno

Summary of the New Models
Two alternative designs for a fuel cell powered car are presented.
Car A, which uses hydrogen fuel, is a sedan designed for the executive market. It provides extra luxury for the driver, but is spacious enough for family use. Car B, powered by hydrogen and oxygen, is a medium-sized Hatchback which offers a range of features for the family. While both cars are efficient for short trips, they lack the range and speed desirable for long journeys.
Both cars incorporate similar safety features and fulfill the design criteria of having low exhaust emissions and using environmentally- friendly materials; however, Car B is recommended as it has slightly lower power consumption and is more economical to manufacture.
Which of following statements is NOT the similarity between Car A and Car B？
A．The safety features of Car A and B are of much resemblance.
B．They both have a desirable range and speed for long journeys.
C．Both share the features of low emission and friendliness to the environment.
D．Both cars are of high efficiency for short travels.

Conflict between the president and the press indicates that ______.
A．the press publishes the truth even when it hurts the president
B．freedom of the press is alive and well in the United States
C．presidents have traditionally had little respect for the press
D．the press is made up mostly of critics and cynics

Which benefits does the job offer？
A．Days off for working nights
B．Bonus for hitting targets
C．Out-store discounts
D．Subsidized travel to work

The passage suggests that issues of a free press ______.
A．have been intertwined with matters concerning the separation of church and state
B．still raise controversy in the United States
C．are clearly discussed in the Constitution of the United States
D．originated during George Washington's administration