diff --git a/Assets/Scripts/StudyCase2/ThirdCharacterController.cs b/Assets/Scripts/StudyCase2/ThirdCharacterController.cs
index c0fc07b..8234109 100644
--- a/Assets/Scripts/StudyCase2/ThirdCharacterController.cs
+++ b/Assets/Scripts/StudyCase2/ThirdCharacterController.cs
@@ -38,11 +38,11 @@ namespace StudyCase2
             moveDir = forward.TransformDirection(moveDir);
             if (moveInput != Vector2.zero)
             {
-                animator?.SetBool("Move", true);
+                animator.SetBool("Move", true);
                 Quaternion target = Quaternion.LookRotation(new Vector3(moveDir.x, 0, moveDir.z));
                 model.rotation = Quaternion.Slerp(model.rotation, target, turnSpeed * Time.deltaTime);
             }
-            else animator?.SetBool("Move", false);
+            else animator.SetBool("Move", false);
             if (!characterController.isGrounded)
                 moveDir.y -= gravity * Time.deltaTime;
             characterController.Move(moveDir * moveSpeed * Time.deltaTime);
diff --git a/Assets/Scripts/StudyCase3/ThirdCharacterController.cs b/Assets/Scripts/StudyCase3/ThirdCharacterController.cs
index 733e367..8f4e64e 100644
--- a/Assets/Scripts/StudyCase3/ThirdCharacterController.cs
+++ b/Assets/Scripts/StudyCase3/ThirdCharacterController.cs
@@ -82,11 +82,11 @@ namespace StudyCase3
             moveDir = forward.TransformDirection(moveDir);
             if (moveInput != Vector2.zero)
             {
-                animator?.SetBool("Move", true);
+                animator.SetBool("Move", true);
                 Quaternion target = Quaternion.LookRotation(new Vector3(moveDir.x, 0, moveDir.z));
                 model.rotation = Quaternion.Slerp(model.rotation, target, turnSpeed * Time.deltaTime);
             }
-            else animator?.SetBool("Move", false);
+            else animator.SetBool("Move", false);
             if (!characterController.isGrounded)
                 moveDir.y -= gravity * Time.deltaTime;
             characterController.Move(moveDir * moveSpeed * Time.deltaTime);