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實(shí)例代碼( Tip: 登錄后體驗(yàn)更佳 )
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"> 
<title>W3Cschool教程(w3cschool.cn)</title> 
<style> 
p:first-of-type
{
    background:#ff0000;
}
</style>
</head>
<body>
<h1>This is a heading</h1>
<p>The first paragraph.</p>
<p>The second paragraph.</p>
<p>The third paragraph.</p>
<p>The fourth paragraph.</p>
</body>
</html>
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