<table border="1">
        <caption>前端三剑客</caption>
        <tr>
            <th>知识点</th>
            <th>重要程度</th>
            <th>难度</th>
            <th>学习周期</th>
        </tr>
        <tr>
            <td>html</td>
            <td>5星</td>
            <td>3星</td>
            <td>7天</td>
        </tr>
        <tr>
            <td>css</td>
            <td>5星</td>
            <td>4星</td>
            <td>10天</td>
        </tr>
        <tr>
            <td>js</td>
            <td>5星</td>
            <td>5星</td>
            <td>20天</td>
        </tr>
    </table>