diff --git a/docs/坦克大战笔记.docx b/docs/坦克大战笔记.docx
index 0e717e5..fe01a06 100644
Binary files a/docs/坦克大战笔记.docx and b/docs/坦克大战笔记.docx differ
diff --git a/src/com/demo/tank/course4/ResourceManager.java b/src/com/demo/tank/course4/ResourceManager.java
index 3a47bce..a64cfab 100644
--- a/src/com/demo/tank/course4/ResourceManager.java
+++ b/src/com/demo/tank/course4/ResourceManager.java
@@ -8,6 +8,7 @@ import java.io.IOException;
 
 public class ResourceManager {
     public static BufferedImage tankL, tankR, tankU, tankD;
+    public static BufferedImage badTankL, badTankR, badTankU, badTankD;
     public static BufferedImage bulletL, bulletR, bulletU, bulletD;
     public static BufferedImage[] explodes = new BufferedImage[16];
 
@@ -18,6 +19,11 @@ public class ResourceManager {
             tankR = ImageUtil.rotateImage(tankU, 90);
             tankD = ImageUtil.rotateImage(tankU, 180);
 
+            badTankU = ImageIO.read(ResourceManager.class.getClassLoader().getResourceAsStream("images/GoodTank1.png"));
+            badTankL = ImageUtil.rotateImage(badTankU, -90);
+            badTankR = ImageUtil.rotateImage(badTankU, 90);
+            badTankD = ImageUtil.rotateImage(badTankU, 180);
+
             bulletL = ImageIO.read(ResourceManager.class.getClassLoader().getResourceAsStream("images/bulletL.gif"));
             bulletR = ImageIO.read(ResourceManager.class.getClassLoader().getResourceAsStream("images/bulletR.gif"));
             bulletU = ImageIO.read(ResourceManager.class.getClassLoader().getResourceAsStream("images/bulletU.gif"));
diff --git a/src/com/demo/tank/course4/Tank.java b/src/com/demo/tank/course4/Tank.java
index 3029409..51c840f 100644
--- a/src/com/demo/tank/course4/Tank.java
+++ b/src/com/demo/tank/course4/Tank.java
@@ -28,16 +28,16 @@ public class Tank {
         //根据方向绘制坦克
         switch (dir){
             case UP:
-                g.drawImage(ResourceManager.tankU, x, y, null);
+                g.drawImage(this.group == Group.GOOD ? ResourceManager.tankU : ResourceManager.badTankU, x, y, null);
             break;
             case DOWN:
-                g.drawImage(ResourceManager.tankD, x, y, null);
+                g.drawImage(this.group == Group.GOOD ? ResourceManager.tankD : ResourceManager.badTankD, x, y, null);
                 break;
             case LEFT:
-                g.drawImage(ResourceManager.tankL, x, y, null);
+                g.drawImage(this.group == Group.GOOD ? ResourceManager.tankL: ResourceManager.badTankL, x, y, null);
                 break;
             case RIGHT:
-                g.drawImage(ResourceManager.tankR, x, y, null);
+                g.drawImage(this.group == Group.GOOD ? ResourceManager.tankR : ResourceManager.badTankR, x, y, null);
                 break;
         }
         move();
@@ -66,6 +66,16 @@ public class Tank {
                 this.randomDirection();
             }
         }
+
+        //边界检测
+        boundsCheck();
+    }
+
+    private void boundsCheck() {
+        if(x < 0) x = 0;
+        if(x > TankFrameV4.GAME_WIDTH - Tank.WIDTH) x = TankFrameV4.GAME_WIDTH - Tank.WIDTH;
+        if(y < 30) y = 30; //算上菜单条
+        if(y > TankFrameV4.GAME_HEIGHT - Tank.HEIGHT) y = TankFrameV4.GAME_HEIGHT - Tank.HEIGHT;
     }
 
     private void randomDirection() {