diff --git a/03：类与对象/01.md b/03：类与对象/01.md
index 9417be7..5429309 100644
--- a/03：类与对象/01.md
+++ b/03：类与对象/01.md
@@ -154,7 +154,7 @@ class Circle {
     float r;
 
     public Circle() {
-        Circle(0, 0, 1);
+        this(0, 0, 1);
     }
 
     public Circle(float x, float y, float r) {