diff --git a/index.php b/index.php
index 20c3b0b..94be05e 100644
--- a/index.php
+++ b/index.php
@@ -1,8 +1,8 @@
 <?php
 
 
-$language = "zh_CN";
-putenv("LANG=".$language);
+$language = 'zh_CN';
+putenv('LANG='.$language);
 setlocale(LC_ALL, [$language, $language.'.utf8']);
 
 require_once __DIR__.'/vendor/autoload.php';