diff --git a/bullet.py b/bullet.py
index d5503a5..61ed5ff 100644
--- a/bullet.py
+++ b/bullet.py
@@ -58,7 +58,6 @@ class BossBullet(Sprite):
 
         self.color = ai_settings.bossbullet_color
         self.speed_factor = ai_settings.bossbullet_speed_factor
-        self.height = ai_settings.bossbullet_height
 
     def update(self):
         """向下移动子弹"""
@@ -66,3 +65,11 @@ class BossBullet(Sprite):
         self.y += self.speed_factor
         # 更新表示子弹的rect的位置
         self.rect.y = self.y
+
+    def reset_position(self, bossalien):
+        """（当子弹飞出屏幕底部或者击中飞船时）回到开始的地方"""
+        self.y = bossalien.rect.bottom
+        self.x = bossalien.x
+        # 更新rect位置
+        self.rect.y = self.y
+        self.rect.x = self.x