diff --git a/webapp/controller/ShopController.class.php b/webapp/controller/ShopController.class.php
index 8fd6826f..93661237 100644
--- a/webapp/controller/ShopController.class.php
+++ b/webapp/controller/ShopController.class.php
@@ -201,9 +201,9 @@ class ShopController extends BaseAuthedController
 
         $goods = mt\ShopGoods::get($id);
         if (!$goods) {
-            $this->_rspErr(1, 'id is invalid. {$id}');
+            $this->_rspErr(1, "id is invalid. {$id}");
         }
-        
+
         if ($goods['shop_id'] == 9 && $goods_num > 1) {
             $this->_rspErr(1, 'goods_num is invalid');
         }