diff --git a/Exercise/exercise-2.1.py b/Exercise/exercise-2.1.py
index 7648898..b0b744a 100644
--- a/Exercise/exercise-2.1.py
+++ b/Exercise/exercise-2.1.py
@@ -2,8 +2,8 @@
 
 list_a = [0]
 
-list_a += ['Hello'] * 5
-list_a += [4, 5] * 3
+
+
 
 # 输出[0, 'Hello', 'Hello', 'Hello', 'Hello', 'Hello', 4, 5, 4, 5, 4, 5]
 print(list_a)
diff --git a/requirements.txt b/requirements.txt
index 2cd046a..03113d1 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -11,4 +11,5 @@ pillow==11.3.0
 pyparsing==3.2.3
 python-dateutil==2.9.0.post0
 scipy==1.16.1
+simpleitk==2.5.2
 six==1.17.0