輸出的內容里怎樣去掉多余的代碼，只把輸出語句中的內容輸出來
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>php語句結束符</title>
</head>
<body>
<p>
??? <?php
??? echo "歡迎同學們！";
??? echo "<br/>";
??? echo "Welcome" . " to imooc!";
??? echo "<br/>";
??? echo 1+2+3+4+5;
??? ?>
</p>
</body>
</html>
我的輸出內容：
<pre><!DOCTYPE HTML> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>php語句結束符</title> </head> <body> <p> ? ?歡迎同學們！Welcome to imooc!15</p> </body> </html>
2017-09-08
那個是多余的輸出的語句!刪除前面的echo