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<section id="sec1">
<h1>header</h1>
<p>paragraph</p>
<section id="sec2">section</section>
<p id="p2">paragraph</p>
</section>
問:哪裏會是在文檔大綱#P2元素?它屬於#sec1還是#sec2?
<section id="sec1">
<h1>header</h1>
<p>paragraph</p>
<section id="sec2">section</section>
<p id="p2">paragraph</p>
</section>
問:哪裏會是在文檔大綱#P2元素?它屬於#sec1還是#sec2?
它屬於#sec1,因爲它不在#秒2中。