Unit 3 Looking good，feeling good【美文阅读】 How to keep fit生命对于我们只有一次，我们有道理也有必要珍惜我们的生命。我们怎样才能延年益寿？An English proverb goes: An apple a day keeps the doctor away. From this we can see a good and balanced diet is very important for one's health. That is a mixture of all kinds of useful substances—carbohydrates(碳水化合物), fats, proteins(蛋白质), fiber, minerals, vitamins, and water. Carbohydrates supply about half of your energy. Proteins are for body building. You need them for growth and for replacing dead cells. Your body also needs small amounts of minerals and vitamins. For example, calcium(钙)is important for making bones and teeth and it is from cheese and milk you eat. You can see nothing at night if you lack vitamin A．Fiber can't be digested(消化), but it is good for your body because it helps food pass through your gut(肠)more easily. You need about a litre of water every day and more if it is hot or you are very active. Drinks, fruits and other foods contain water in them.The public opinionAll living things need food. Good and suitable foods really have much to do with good health. If poisonous( 有毒的)chemicals get into food, they can kill living things. So we can't eat polluted food and we can't drink polluted water. What's worse, with the development of modern agriculture and industry, more and more waste is produced. Agriculture and industry should not go against nature. We should take science, technology and balance of the nature into accounts in agriculture and industry.A middle school teacherI think we should form good habit of life. We should eat three meals in correct time. Smoking is harmful to our health. It is a pity that there are...
