阅读理解。
Imagine reading one day that you had been a subject in a risky science experiment without knowing it.
At school, you had been fed cereal laced with radioactive chemicals so scientists could learn more about
the digestive system. Because the food was radioactive, scientists could easily trace its path through the
body.
Scientists now know that exposure to large amounts of radiation can cause cancer, a group of diseases
in which bodily cells grow wildly out of control. Some people who were part of the radiation studies later
developed cancer and blame the radiation for causing the cancer. Others are worried the radiation will
someday make them sick.
Some doctors say that, in many cases, such fears are unjustified because the radiation doses (剂量) used
in the experiments were too small to cause harm. They also say that since the dangers of radiation were less
well understood then than they are now, even researchers who used high doses of radiation didn't do anything
wrong.
Some critics claim that no excuse is acceptable for not informing subjects about the nature of an experiment
and giving them a chance to refuse to participate. Today, government rules require such informed agreement
whenever a study uses people.
1. The passage is mainly about _____.
A. what kinds of experiment cannot be done on people
B. whether it is moral to experiment on people without telling them
C. what result can be obtained in a radioactive experiment
D. how radiation studies are conducted
2. Which of the following statements is TRUE according to the passage?
A. Human cells can be excited by the radiation to grow wildly out of control.
B. As long as the danger of radiation has not been proved, high doses of it can also be acceptable.
C. Most cancers are caused by radiation.
D. Any exposure to radiation will surely cause cancer.
3. The government rules demand _____.
A. to stop all experiments harmful to people
B. to prohibit all the experiments on humans
C. to licence all the tests related to human beings
D. to protect people's human right not to be tested without permission
4. Which of the following words best describes the author's attitude towards the government decision?
A. negative
B. indifferent
C. critical
D. favourable