A、He began to use chemicals. B、He preserved food with sugar. C、He sealed food in jars. D、He kept food in cans. C关键词是French man，听

How do you preserve your food? Let’s take a discussion. Someone will say, put it in the refrigerator. And ask a question, before we invented the refrigerator, in which way could we keep the food longer or we say if we didn’t have the refrigerator, in what container or some place to keep the food? So think about it more and deeply.
     The search for ways of preserving foods is not new. Early man learned that he could make foods last by drying them. (26) The Indians, for instance, hung deer meat in the sun. The greatest advance began in 1800 when (27) a French man discovered that he could preserve certain foods by sealing them in jars and keeping the air from them. The process was the beginning of the vast canning industry, which brings us a variety of foods in all seasons. Fruits are often preserved by drying. The use of chemicals is another method, and some foods are cooked with sugar. But recently, the method of preserving food by freezing has grown tremendously, and more foods than ever before are now being processed by freezing.
     And nowadays we usually keep it in the refrigerator, and even didn’t know the other or former methods. Maybe we could try some other new ways to handle this problem. With the developing society, and the developing technology, the better we think of, the better life we get. (28) Food keeping is so important in our dally life and everyone needs to eat. How to deal with the left one? Just throw it away is wasting and maybe you want to eat someday. So we should think the credible way to handle it.