php fwrite如何同時(shí)寫入多個(gè)變量？

<?php
$name="姓名:".$_POST['name']."\r\n";
$tel="電話:".$_POST['tel']."\r\n";
$auto="車型:".$_POST['auto']."\r\n";
$fp=fopen("auto.txt","w");
fwrite($fp,$name);
fwrite($fp,$tel);
fwrite($fp,$auto);

如何不寫3次fwrite？