Our Muscles ①When we think of muscles, we might often picture abodybuilder with big arm and leg muscles. But our muscles do not have to looklike that to work well. ②As a matter of fact, every time we write our name, we use the20 different muscles in our hand. Every time our heart beats, we use ourcardiac muscles (心肌). When we eat our food, we use our tongue muscles. We evenuse muscles when we open and close our eyes. In fact, every time we move, weuse some of the muscles in our body. ③A muscle is made of tiny fibers. Fiber is a type of tissuethat feels a little like a rubber band. Thousands of these fibers are packedtogether to make a single muscle. We all have the same number of muscles --about 700 or so. Men and women with big muscles simply have thicker bundles offibers. ④There are three different types of muscles in our body.Smooth muscles are the ones that we cannot control. They work quietly to keepour body running. Also, they are the ones that help us to absorb our food. Thecardiac muscle makes the heart pump blood in and out. Skeletal muscles are theones that we can control. These are the muscles that we use to raise our hands,or ride our bicycles. ⑤Even our face often uses muscles. But if we want to save ourenergy, try smiling instead of frowning. Remember that it takes 17 muscles inour face to smile, but 43 muscles to frown! 翻译上述文章
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