diff --git a/book/en-us/02-usability.md b/book/en-us/02-usability.md
index eb8a21a..0db99fa 100644
--- a/book/en-us/02-usability.md
+++ b/book/en-us/02-usability.md
@@ -880,7 +880,7 @@ public:
     void free(T& item);
 private:
     T data[BufSize];
-}
+};
 
 buffer_t<int, 100> buf; // 100 as template parameter
 ```
diff --git a/book/zh-cn/02-usability.md b/book/zh-cn/02-usability.md
index e9c84e9..68f83f4 100644
--- a/book/zh-cn/02-usability.md
+++ b/book/zh-cn/02-usability.md
@@ -788,7 +788,7 @@ public:
     void free(T& item);
 private:
     T data[BufSize];
-}
+};
 
 buffer_t<int, 100> buf; // 100 作为模板参数
 ```