根据材料请回答 31～35 Vegetarian A strict vegetarian is a person who never in his life eats anything derived from(来自于)animals.The main objection to vegetarianism on a long-term basis is the difficulty of getting enough protein(蛋白质), the body-building elements in food.If you have ever been without meat or animal foods for some days or weeks, say, for religious reasons, you will have noticed that you tend to get physically weak.You are glad when the fast(斋戒)is over and you get your reward of a great meat meal. Proteins are built up from approximately twenty food elements called 'amino-acids'(氨基酸), which are found more abundantly in animal protein than in vegetable protein.This means you have to eat a great deal more vegetable than animal food in order to get e-nough of these amino-acids. A great deal of the vegetable food goes to waste in this process and from the physiological point of view there is not much to be said in favor of life-long vegetarianism. The economic side of the question, though, must be considered.Vegetable food is much cheaper than animal food.However, since only a small proportion of the vegetable protein is useful for body-building purposes, a consistent (坚定的) vegetarian, if he is to gain the necessary 70 grams of protein a day, has to consume a greater bulk of food than his digestive organs can comfortably deal with.In fairness, though, it must be pointed out that vegetarians claim they need far less than 70 grams of protein a day. Whether or not vegetarianism should be advocated for adults, it is definitely unsatis- factory for growing children, who need more protein than they can get from vegetable sources. There is a lacto-vegetarian(乳酸素食者)diet which includes milk and milk products .Meat and cheese are the best sources of usable digestible protein and next come milk, fish and eggs.Slow and careful cooking of meat makes it more digestible and assists in the breaking, down of the protein content by the body.When cooking vegetables, however ,the vitamins, and in particular the water-soluble(性) vitamin C, should not be lost through over-cooking. 第 31 题 A vegetarian is a person who