托福考试

【分析解答题】loon birds have two types of feather to protect them in the cold water, they are water birds live in cold climate in northAmerica, 1st, counterfeit (不确定), feather which is the outer layer of the birds’ body. This type of feather keeps the birds dry, it is packed tightly and olily wich keep the water going into the body. 2nd type, is down feather, wich keeps the bird warm. It is dense and thick and is make of soft fluffy material. So it prevents the heat loosing for the body
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