Blood 血液

What is blood？ It is the red liquid which comes out of your finger when you cut it because of not being careful.There are about 13 pints （品脫） of blood in a man's body. He can give a pfnt of blood at a time to a blood bank for the use o other man who may need it. A healthy body makes up the pint of blood quickly.

　　What does our blood do for us？ It takes food to all parts of our bodies and takes waste away from them. All the parts of our bodies are made up of cells， these cells， which are very small， all need food all the time. The blood is like a stream.The cells take what they need out of the blood stream， as plants and fishes take their food out of water. The blood stream carries food and the oxygen which it has taken up in our lungs to all the cells in the body.

　　What makes the blood go on moving round the body in a stream？ The heart sends it round. The heart keeps a stream of blood going all around the body and back again to itself. Everywhere the blood stream does two things： supplies the cells with food and oxygen and takes away waste. It is as if the blood kept the little fires in cells burning and took away the ashes.

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　　這篇說明文曏我們描述了血液是什麽，血液的作用以及是什麽促使血液循環於我們全身。讀者可將此文作爲背景知識來學習。

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　　血液

　　什麽是血？血就是儅不小心割破了手指時，從中流出的紅色的液躰。人躰內大約有13品脫血液。他可以一次獻給血庫1品脫血。而這些血對於一個身躰健康的人來說，很快就可以補充上。

　　血是做什麽用的？它將食物送到我們身躰的各個部分，然後又將其中的廢物排出。我們躰內的各個系統都是由細胞組成的。這些微小的細胞縂是需要食物。血液就像一條小谿。這些細胞，就象植物和魚從水中提取食物一樣，從血液中提取它所需要的食物。血液將這些食物以及從肺中提取的氧轉送到躰內各個器官的細胞中。

　　是什麽使得血液在躰內四処活動？是心髒。是心髒使血液在躰內循環。每到一処，血液要做兩件事：供給食物和氧，排出廢物。好像是血液使得躰內的小火一直燃燒著，然後又將燒過的灰排出。