用户注册php出错

我正在做一个简单的用户注册这给我一些错误，我像1小时看到其他问题和答案，但没有什么可以解决我的问题，所以这里是

FIRST OF ALL MY register.php

<?php
if(!empty($_POST['username']) && !empty($_POST['password']))
{
$username = mysqli_real_escape_string($_POST['username']);
$password = md5(mysqli_real_escape_string($_POST['password']));
$email = mysqli_real_escape_string($_POST['email']);
 $checkusername = mysqli_query("SELECT * FROM users WHERE Username = '".$username."'");
 if(mysqli_num_rows($checkusername) == 1)
 {
    echo "<h1>Error</h1>";
    echo "<p>Sorry, that username is taken. Please go back and try again.</p>";
 }
 else
 {
    $registerquery = mysqli_query("INSERT INTO users (Username, Password, EmailAddress) VALUES('".$username."', '".$password."', '".$email."')");
    if($registerquery)
    {
        echo "<h1>Success</h1>";
        echo "<p>Your account was successfully created. Please <a href='"index.php'">click here to login</a>.</p>";
    }
    else
    {
        echo "<h1>Error</h1>";
        echo "<p>Sorry, your registration failed. Please go back and try again.</p>";   
    }      
 }
}
else
{
?>
 <h1>Register</h1>
 <p>Please enter your details below to register.</p>
<form method="post" action="register.php" name="registerform" id="registerform">
<fieldset>
    <label for="username">Username:</label><input type="text" name="username" id="username" /><br />
    <label for="password">Password:</label><input type="password" name="password" id="password" /><br />
    <label for="email">Email Address:</label><input type="text" name="email" id="email" /><br />
    <input type="submit" name="register" id="register" value="Register" />
</fieldset>
</form>
<?php
}
?>

NOW MY conconion .php

<?php
//Conexión a la base de datos
$servidor = "localhost"; //Nombre del servidor
$usuario = "myuser"; //Nombre de usuario en tu servidor
$password = "mypass"; //Contraseña del usuario
$base = "db_maquinas"; //Nombre de la BD
//conection:
$link = mysqli_connect("$servidor","$usuario","$password","$base") or die("Error " . mysqli_error($link));
?>

这些错误给了我

警告:mysqli_real_escape_string()期望2个参数，1在C:'xampp'htdocs'maquinas2000'paginas'register.php第14行

警告:mysqli_real_escape_string()期望2个参数，1在C:'xampp'htdocs'maquinas2000'paginas'register.php第15行

警告:mysqli_real_escape_string()期望2个参数，1在C:'xampp'htdocs'maquinas2000'paginas'register.php第16行

警告:mysqli_query()期望至少2个参数，1在C:'xampp'htdocs'maquinas2000'paginas'register.php第18行

警告:mysqli_num_rows()期望参数1为mysqli_result, null在C:'xampp'htdocs'maquinas2000'paginas'register.php第20行

警告:mysqli_query()期望至少2个参数，1在C:'xampp'htdocs'maquinas2000'paginas'register.php第27行

我知道是关于mysqli，但我试图找出它，但没有发生相同的错误。之前给了我更多的错误…我解决了一些问题，但仍然有错误。THX