php fwrite如何同时写入多个变量？

Question

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

如何不写3次fwrite？