Three Yale University professors agreed in a discussion that the automobile was what one of them called “Public Health Enemy No. 1 in this century”. Besides polluting the air and overcrowding the cities, cars are involved in more than half the disastrous accidents, and they contribute to heart disease “because we won’t walk anywhere any more,” said Richard Weeinaman, professor of medicine and public health.
Speaking of many of those man-made dangers of the automobile, Arthur W. Galson, professor of biology, said it was possible to make a kerosene-burning turbine car that would “lessensmog by a very large factor”. But he expressed doubt whether Americans were willing to give up moving about the countryside at 90 miles per hour in a large vehicle. “America seems wedded to the motor car—every family has to have at least two, and one has to be a convertible (敞篷汽车) with 300 horsepower,” professor Galson continued. “Is this the way of life that we choose because we treasure these values?”
For professor Sears, part of the blame lies with “a society that regards profit as a supreme value, under the illusion that anything that’s technically possible is, therefore, morally justified”. Professor Sears also called the country’s dependence on its modern automobiles “terrible economics” because of the large horsepower used simply “moving one individual to work”. But he admitted that Americans have painted themselves into a corner by allowing the national economy to become so dependent on the automobile industry.
“The solution,” Dr Weeinerman said, “is not finding a less dangerous fuel but a different system of inner city transportation. Because of the increasing use of cars, public transportation has been allowed to wither (衰弱) and grow worse, so that if you can’t walk to where you want to go, you have to have a car in most cities,” he declared. This, in turn, Dr Weeinerman contended, is responsible for the “arteriosclerosis (动脉硬化)” of public roads, for the pollution of the inner city and for the middle-class movement to the suburbs.
The main idea of the passage is that         .

A．Americans are used to travelling by cars

B．American public transportation is growing worse

C．American car industry caused disastrous road accidents

D．American people’s health is threatened by automobiles

It can be inferred from the passage that        .

A．Americans prefer cars to anything else

B．Americans are interested in fast automobiles

C．kerosene-burning engines cause more problems

D．kerosene-burning engines are green transportation

In Paragraph 3, Professor Sears implies that         .

A．technology is always good for people

B．technology is a sword with two sides

C．more attention should be paid to social effects

D．US doesn’t care about the environment at all