题目内容：

A food additive (添加剂) is any substance that is added to food. Many people are put off by the idea of “chemicals in food.” The truth is that all food is made up of chemicals. Natural substances like milk, as well as man-made ones like drinks on sale in the market, can be described by chemical formulas. Some chemical substances are indeed harmful, but a person who refused to consume any chemicals would find nothing to eat.

The things we eat can be divided into natural and man-made substances. Some people feel that only natural foods are healthy and that all man-made ingredients are to be avoided. But many natural chemicals, found in plants and animals, are harmful when eaten, and some laboratory-made substances increase the nutritional value of food. Other chemicals have natural and man-made forms that are exactly alike: vitamin C is vitamin C, whether it comes from a test tube or from an orange. Like “chemical”, “man-made” doesn’t necessarily mean “not fit to eat”.

Food additives are used for many reasons. We add sugar and salt and other things to foods we prepare at home to make them taste better. Food producers have developed a range of additives that stabilize（使稳定）, thicken, harden, keep wet, keep firm, or improve the appearance of their products. Additives can make food more convenient or nutritious, give it a longer shelf life, and make it more attractive to the consumer, thus increasing the sales and profits of the producers.

Food additives are presently the centre of a storm of serious argument. Food producers have been known to use additives that have not been proved safe; some substances in common use have been proved unsafe and have been taken off the market. Many people feel there’s a risk of eating food to which anything has been added. But food additives are now regulated by the FDA of the federal government, and new additives will go through strict testing before they can be placed on the market. For most people, the chances of developing serious side effects (副作用) from the long-term use of presently approved (批准) food additives are very small.

1.From the passage we can learn that        .

A. natural foods are much safer than man-made ones

B. it is right to refuse chemicals in food

C. food additives are harmful to our health

D. all foods have chemical substances

2.Which of the following is TRUE according to the passage?

A. Food additives can improve the quality of foods in many ways.

B. To ensure food safety, the FDA will stop food additives.

C. Foods free of additives can keep a much longer shelf life.

D. Foods with more additives have higher nutritional value.

3.We can infer from the regulation to the food additives by the FDA that        .

A. new additives will be approved more easily than before

B. food with common-used additives will be taken off the market

C. food additives will be used in a safer and more scientific way

D. food producers won’t be allowed to use new food additives

4.According to the writer, the food additive is        .

A. worrying        B. acceptable

C. poisonous       D. avoidable