[单项选择]

A number of persons have expressed concern about possible health dangers to workers who use devices called video-display terminals (终端) or VDTs. These are the devices used to show computer information. Some reports link VDTs to health disorders including eye problems and muscle problems. Even the health of the pregnant women and their unborn babies is said to be endangered. Video-display terminals produce low levels of the electromagnetic radiation(电磁辐射). Experts say most modern VDTs have been designed to limit the dangers from such radiation. However, study shows that even low levels of electromagnetic radiations can affect the growth of the cells. As a result, some doctors advise women to stop working with VDTs while they are pregnant. One study found women who work with VDTs in early pregnancy are more likely than others to have their pregnancy end unexpectedly. Researchers said that this does not necessarily mean that VDTs themselves cause problems. Some exper
A. to do other work than on VDTs
B. to change their computers if necessary
C. to go back home to have a rest
D. to have their health tested

[单项选择]

A number of persons have expressed concern about possible health dangers to workers who use devices called video-display terminals (终端) or VDTs. These are the devices used to show computer information. Some reports link VDTs to health disorders including eye problems and muscle problems. Even the health of the pregnant women and their unborn babies is said to be endangered. Video-display terminals produce low levels of the electromagnetic radiation(电磁辐射). Experts say most modern VDTs have been designed to limit the dangers from such radiation. However, study shows that even low levels of electromagnetic radiations can affect the growth of the cells. As a result, some doctors advise women to stop working with VDTs while they are pregnant. One study found women who work with VDTs in early pregnancy are more likely than others to have their pregnancy end unexpectedly. Researchers said that this does not necessarily mean that VDTs themselves cause problems. Some exper
A. can change the working conditions for the operators
B. can limit the dangers from the electro-magnetic radiation
C. can also affect the growth of the cells
D. can protect the health of the computer operators

[单项选择]A number of theories have been put forward about the possible causes of cancer.
A. 理论上早已预言了癌症的病因。
B. 人们就造成癌症的病因提出了许多理论。
C. 大量的理论已经用于解释引发癌症的原因。
D. 人们已经用大量理论来研究癌症的病因。

[单项选择]The number about reported thefts and convictions is used to illustrate that ______.
A. thefts have decreased considerably
B. crime does not pay
C. crime rate has risen
D. legal deterrents are not strong

[单项选择]One common concern of writers about "free writing" is that ______.
A. it overstresses the role of the creative mind
B. it takes too much time to edit afterwards
C. it may bring about too much criticism
D. it docs not help them to think clearly

[单项选择]His teacher ______ concern about the progress he had made at school.


A. expressed
B. exported
C. exploded
D. exposed

[单项选择]Recently, people more concern about _________.

[单项选择]What is the concern of ordinary people about the greenhouse effect


A. Whether it can be detected and checked.
B. Whether it will lead to widespread food shortage.
C. Whether global warming will speed up in the future.
D. Whether it will affect their own lives.

[单项选择]A number of theories have been proposed to explain the situation.
A. suggested
B. tested
C. used
D. announced