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<center>How are you?</center>
<h1>How are you?</h1>
<h2>How are you?</h2>
<h3>How are you?</h3>
<h4>How are you?</h4>
<h5>How are you?</h5>
<h6>How are you?</h6>
<i>How are you?</i>
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<p>How are you?</p>
<p>我 很 好 啊</p>
<p><b>how about you?<br>Me?</b></p>
<p><b>I am crazy ! !</b></p>
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<p>10<sup>2</sup></p>
<p><del>I'm going to delete you,bitch</del></p>
<p><u>Add one underline to this sentence.</u></p>
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标签嵌套的规范：
