[填空题]Sugarless food, such as ______ ,plays a role in the prevention of tooth decay.

[填空题]Sugarless food, such as ______ ,plays a role in the prevention of tooth decay.

[单项选择]I had great difficulty （　） the suitable food on the menu in that restaurant.
A. find
B. found
C. to find
D. finding

[单项选择]Ocean water plays an indispensable role in
supporting life. The great ocean basins hold about
300 million cubic miles of water. From this vast
Line amount, about 80,000 cubic miles of water are
(5) sucked into the atmosphere each year by evapora-
tion and returned by precipitation and drainage to
the ocean. More than 24,000 cubic miles of rain
descend annually upon the continents. This vast
amount is required to replenish the lakes and
(10) streams, springs and water tables on which all
flora and fauna are dependent. Thus, the hydro-
sphere permits organic existence.
The hydrosphere has strange characteristics
because water has properties unlike those of any
(15) other liquid. One anomaly is that water upon
freezing expands by about 9 percent, whereas
most liquids contract on cooling. For this reason,
ice floats on wat
A. describe the properties and uses of water
B. illustrate the importance of conserving water
C. explain how water is used in commerce and industry
D. reveal the extent of the earth’s ocean masses
E. (E) compare water with other liquids

[填空题]Parental involvement plays a limited role in preventing teenage use of drug.

[简答题]

We all know that science plays an important role in the societies in which we live. Many people believe, however, that our progress depends on two aspects of science. The first of which is the machines, products and systems of applied knowledge that scientists and technologists develop. Through technology, science improves that structure of society and helps man to gain increasing control over his environment. 46)The second aspect is the application by all members of society from the government official to the ordinary citizen, of the special methods of thought and action that scientists use in their work.
47)Human beings have distinguished themselves from other animals, and in doing so ensured their survival, by the ability to observe and understand their environment and then either to adapt to that environment or to control and adapt it to their own needs. The process of careful observation, perception of a pattern in the phenomena observed, followed by ex

[单项选择]

The belief that the mind plays an important role in physical illness goes back to the earliest days of medicine. From the time of the ancient Greeks to the beginning of the 20th century, it was generally accepted by both physician and patient that the mind can affect the course of illness, and it seemed natural to apply this concept in medical treatments of disease. After the discovery of antibiotics, a new assumption arose that treatment of infectious or inflammatory disease requires only the elimination of the foreign organism or agent that triggers the illness. In the rush to discover new antibiotics and drugs that cure specific infections and diseases, the fact that the body’s own responses can influence susceptibility to disease and its course was largely ignored by medical researchers.
It is ironic that research into infectious and inflammatory disease first led 20th-century medicine to reject the idea that the mind influences physical illness, and now researc
A. The responsivity to stress is genetically determined
B. The treatment of immune maladies can be consciously controlled
C. Psychoactive drugs may in some cases be used to treat inflammatory diseases
D. Social interactions can lessen psychological stress and alter immune responses