传声器按时间发展的顺序依次是
B
暂无解析
The physicists propose that our attention____the use of special methods of thinking and acting.
The food we eat seems to have profound effects on our health. Although science has made enormous steps in making food more fit to eat, it has , atthe same time, made many foods unfit to eat. Some research has shown that perhaps eighty percent of cancer is related to the diet as well, especially cancer the colon . Different cultures are more prone to contract certain illnesses because of the food that is characteristic in these cultures. That food related to llness is not a new discovery. In 1945 , government researchers realized that itrates and nitrites, commonly used to preserve color in meats, and other food dditives, caused cancer. Yet, these carcinogenic additives remain in our food, nd it becomes more difficult all the time to know which things on the pack ging labels of processed food are helpful or harmful.The additives which we eat are not all so direct. Farmers often give penicillin to beef and poultry, and because of this, penicillin has been found in the milk of treated cows. Sometimes similar drugs are administered to animals not for medicinal purposes, but for financial reasons. The farmers are simply trying to fatten the animals in order to obtain a higher price on the market. Although the Food and Drug Administration (FDA) has tried repeatedly to controlthese procedures, the practices continue.
48. What is the main topic of the passage?
A. Food and our health
B Food and additives
C. Food and cancer
D Food and culture
49 All of the following statements are true EXCEPT_______.
A Forty percent of cancer is caused by problems related to food.
B Researchers have known about the potential danger of food additivesfor many years
C. We eat some of the food additives directly and some indirectly
D Drugs are always given to animals for medicinal purposes
50. Why do farmers give drugs to their animals?
A. to speed up the growth of animals
B To make theanimals fatter
C to make the animals ’ meat fit to eat
D To make the animals’ meat rich in nutrients
51. It can be inferred from the passage that_________.
A scientist have made all the food fit to eat
B only in recent years have people found that the food is related to one’s illness
C all kinds of cancer are related to the diet
D some additives are harmful to our health
52. The word “ this ”in the second sentence of paragraph 2 most probablyrefers to __________.
A farmer
B penicillin
C beef and poultry
D the fact that farmers often give penicillin to a beef