diff --git a/basic_content/sizeof/README.md b/basic_content/sizeof/README.md
index 4fd0e12..6ddb25c 100644
--- a/basic_content/sizeof/README.md
+++ b/basic_content/sizeof/README.md
@@ -145,7 +145,7 @@ class A1
 {
     virtual void fun(){}
 };
-class C1:public A
+class C1:public A1
 {
 };