diff --git a/w5/ShapeAreaCalculator.java b/w4/ShapeAreaCalculator.java
similarity index 100%
rename from w5/ShapeAreaCalculator.java
rename to w4/ShapeAreaCalculator.java
diff --git a/w5/屏幕截图 2026-03-29 185330.png b/w4/屏幕截图 2026-03-29 185330.png
similarity index 100%
rename from w5/屏幕截图 2026-03-29 185330.png
rename to w4/屏幕截图 2026-03-29 185330.png
diff --git a/w5/类图 b/w4/类图
similarity index 100%
rename from w5/类图
rename to w4/类图
diff --git a/w5/DuoTai.java b/w5/DuoTai.java
new file mode 100644
index 0000000..e69de29
diff --git a/w6/AnimalTest.java b/w6/AnimalTest.java
new file mode 100644
index 0000000..8ab4b78
--- /dev/null
+++ b/w6/AnimalTest.java
@@ -0,0 +1,56 @@
+package main.w6;
+
+// 1. 抽象动物类
+abstract class Animal {
+    // 抽象方法：动物叫声
+    public abstract void makeSound();
+}
+
+// 2. 游泳接口
+interface Swimmable {
+    void swim();
+}
+
+// 3. Dog类：继承Animal，实现Swimmable接口
+class Dog extends Animal implements Swimmable {
+    @Override
+    public void makeSound() {
+        System.out.println("小狗汪汪叫~");
+    }
+
+    @Override
+    public void swim() {
+        System.out.println("小狗会狗刨游泳");
+    }
+}
+
+// 4. Cat类：仅继承Animal，不实现Swimmable
+class Cat extends Animal {
+    @Override
+    public void makeSound() {
+        System.out.println("小猫喵喵叫~");
+    }
+}
+
+// 测试类
+public class AnimalTest {
+    public static void main(String[] args) {
+        // 多态调用：父类引用指向子类对象
+        Animal dog = new Dog();
+        Animal cat = new Cat();
+
+        // 调用叫声方法
+        System.out.println("=== 动物叫声 ===");
+        dog.makeSound();
+        cat.makeSound();
+
+        // 只有实现了Swimmable的对象才能调用swim()
+        System.out.println("\n=== 游泳能力 ===");
+        if (dog instanceof Swimmable) {
+            ((Swimmable) dog).swim();
+        }
+
+        // cat没有实现Swimmable，不能调用swim()
+        System.out.println("小猫不会游泳");
+    }
+}
\ No newline at end of file