diff --git a/zh/02.5.md b/zh/02.5.md
index 3038f330..4c2a0b39 100644
--- a/zh/02.5.md
+++ b/zh/02.5.md
@@ -177,7 +177,7 @@ func (bl BoxList) BiggestColor() Color {
 }
 
 func (bl BoxList) PaintItBlack() {
-	for i, _ := range bl {
+	for i := range bl {
 		bl[i].SetColor(BLACK)
 	}
 }