diff --git a/73. 抛出与抽象对应的异常.md b/73. 抛出与抽象对应的异常.md
index 2b0cf20..f7f2212 100644
--- a/73. 抛出与抽象对应的异常.md	
+++ b/73. 抛出与抽象对应的异常.md	
@@ -38,7 +38,7 @@ public E get( int index ) {
 try {
 ... // Use lower-level abstraction to do our bidding
 } catch (LowerLevelException cause) {
-throw new HigherLevelException(cause);
+    throw new HigherLevelException(cause);
 }
 ```