This electronic superhighway is called the Internet,（ ）it is the backbone(主干)of the World Wide Web.

A.and B.yet C.or D.while

I do not remember（ ）to Professor Johnson during my visit to Yale.

A.having introduced B.having been introduced C.introducing D.to have been introduced

We（ ）our breakfast when an old man came to the door.

A.just have had B.have just had C.just had D.had just had

The flowers languished from lack of water.

A.withered B.flourished C.vanished D.stopped growing

I’m acting as（ ）while the manager is away on business.

A.agency B.policy C.deputy D.colleague

carcinogenic'="" most="" nearly="" means="" ‘（="" ）="" ’="" . '>

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, at the same time, made many foods unfit to eat. Some research has shown that perhaps eighty percent of all human illnesses are related to diet and forty percent of cancer is related to the diet as well, especially cancer of the colon. Different cultures are more likely to cause certain different illnesses because of the food that is characteristic in these cultures. That food is related to illness is not a new discovery. In 1945, about 35 years ago, government researchers realized that nitrates, commonly used to preserve color in meats, and other food additives, caused cancer. Yet, these carcinogenic additives remain in our food, and it becomes more difficult all the time to know which things on the packaging 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 living animals, and because of this, penicillin has been found in the milk of treated cow. Sometimes similar drugs are given to animals not for medical 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 control these procedures, the practices continue.

1.What is the best possible title of the passage?2.Which of the following statements is NOT true?3.How has science done something harmful to mankind?4.What are nitrates used for?5.The word 'carcinogenic' most nearly means ‘（ ） ’ .

A.Drug and Food B.Cancer and Health C.Food and Health D.Health and Drug问题2： A.Drugs are always given to animals for medical reasons B.Some of the additives in our food are added to the food itself and some are given to the living animals C.Researchers have known about the potential dangers of food additives for over thirty-five years. D.Food may cause forty percent of cancer in world.问题3： A.Because of science, diseases caused by polluted food haven been virtually eliminated B.It has caused a lack of information concerning the value of food. C.Because of the application of science, some potentially harmful substances have been added to food. D.The scientists have preserved the color of meats, but not of vegetables问题4： A.They preserve flavor in packaged foods. B.They preserve the color of meats C.They are the objects of research D.They cause the animals to become fatter问题5： A.trouble-making B.color-retaining C.money-making D.cancer-causing