Do you wear glasses? 你戴眼镜吗？

　　How about contact lenses? 隐形眼镜呢？

　　Do you know what the similarities between glasses and contact lenses are? 你知道眼镜和隐形眼镜的相同之处有哪些吗？

　　They help you see objects better. 它们帮助你更好地看清物体。

　　How can they do that? 它们是怎样做到的？

　　Glasses and contact lenses improve your eyesight, because both of them use some kind of lens. 眼镜和隐形眼镜之所以能改善你的视力，是因为它们都使用某种镜片。

　　Generally, there are two kinds of lenses. 一般来说，镜片有两种。

　　One kind of lens makes you see things bigger. 一种镜片能放大物体。

　　These kinds of lenses are used for magnifying glasses or glasses for old people. 这种镜片用来做放大镜或老花镜。

　　Another kind of lens makes you see things smaller. 另一种镜片能缩小物体。

　　These are used for usual glasses. 这些镜片用来做普通的眼镜。