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2017届高考英语二轮专题复习精品阅读理解部分之限时训练（三） 阅读理解 Drinking water is so important for health. How much water you need in order to be a healthy human being? Why You Need to Drink Water Your body is estimated to be about 60 to 70 percent water. Blood is mostly water, and your muscles, lungs, and brain all contain a lot of water. Your body needs water to regulate body temperature and to provide the means for nutrients to travel to all your organs. Water also transports oxygen to your cells, removes waste, and protects your joints and organs. Signs of Dehydration You lose water through urination, respiration, and sweating. If you are very active, you lose more water than if you are sedentary. Thirst is an obvious sign of dehydration and in fact, you need water long before you feel thirsty. How Much Water do You Need to Drink A good estimate is to take your body weight in pounds and divide that number in half. That gives you the number of ounces of water per day that you need to drink. For example, if you weigh 160 pounds, you should drink at least 80 ounces of water per day. If you exercise you should drink another eight ounce glass of water for every 20 minutes you are active. If you drink alcohol, you should drink at least an equal amount of water. When you are traveling on an airplane, it is good to drink eight ounces of water for every hour you are on board plane. | 
