上标和下标

<sup>用来标记作为上标的字符，表示幂的数学概念。<sub>用来标记为下标的字符，常用在脚注或化学式中。

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        <title>上标和下标</title>
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        <div>化学方程式</div>
        <p>2<sup>2</sup></p>       
                <p>2Mg+O<sub>2</sub>点燃2MgO</p>
                <p>3Fe+2O<sub>2</sub>点燃Fe<sub>3</sub>O<sub>4</sub></p>
                <p>4Al+3O<sub>2</sub>点燃2Al<sub>2</sub>O<sub>3</sub></p>
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posted @ 2018-07-18 09:24  梦人亭  阅读(1464)  评论(0)    收藏  举报