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        新托福閱讀練習(xí)資料:脫水下人類的存活時(shí)間

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            水是生命之源,人類的生存不能離開水。在脫水的情況下人類能活多長時(shí)間呢?接下來的新托??荚囬喿x練習(xí)資料就來討論這個(gè)話題。
            

            If I were to stop drinking water right now, how long could I live?
            There are different factors involved here. A human being isn’t an automobile which needs a certain amount of gas. There are conditions under which a person could die of dehydration within a single day, and other conditions whereby a person might live for over a week. It’s unlikely, though, anyone could go much beyond that.
            Water comes into our systems not just from drinking but from eating as well. It goes out of us through urine, through sweat, and even through exhaling. Ever notice the fog you can make on a window by breathing on it? That’s water vapor leaving your body.
            The biggest reason it’s bad to lose too much water is that the actual volume of your blood goes down. When blood volume goes down, blood pressure goes down. As blood pressure goes down, body heat goes up, because your blood helps regulate your core body temperature. Without enough blood, you can’t cool off. Pretty soon you overheat.
            So various factors, from eating to circulatory health to the ambient temperature, play a part in how long you could go without water. Probably the biggest factor, though, is simply age: young people are much more likely to overheat faster than adults, which is why it’s especially important to keep an eye on the little ones on hot summer days.