diff --git a/w6/Animal.java b/w6/Animal.java
new file mode 100644
index 0000000..94d6f08
--- /dev/null
+++ b/w6/Animal.java
@@ -0,0 +1,5 @@
+package Sound;
+
+public abstract class Animal {
+    public abstract void makeSound();
+}
diff --git a/w6/Cat.java b/w6/Cat.java
new file mode 100644
index 0000000..c42195e
--- /dev/null
+++ b/w6/Cat.java
@@ -0,0 +1,8 @@
+package Sound;
+
+public class Cat extends Animal{
+    @Override
+    public void makeSound(){
+        System.out.println("喵喵");
+    }
+}
diff --git a/w6/Dog.java b/w6/Dog.java
new file mode 100644
index 0000000..7e0d040
--- /dev/null
+++ b/w6/Dog.java
@@ -0,0 +1,12 @@
+package Sound;
+
+public class Dog extends Animal implements Swimmable{
+    @Override
+    public void makeSound(){
+        System.out.println("汪汪");
+    }
+    @Override
+    public void swim(){
+        System.out.println("小狗在游泳");
+    }
+}
diff --git a/w6/Main.java b/w6/Main.java
new file mode 100644
index 0000000..1873862
--- /dev/null
+++ b/w6/Main.java
@@ -0,0 +1,14 @@
+package Sound;
+
+public class Main{
+    public static void main(String[] args){
+        Animal dog = new Dog();
+        Animal cat = new Cat();
+
+        dog.makeSound();
+        cat.makeSound();
+
+        Dog myDog = new Dog();
+        myDog.swim();
+    }
+}
\ No newline at end of file
diff --git a/w6/Swimmable.java b/w6/Swimmable.java
new file mode 100644
index 0000000..16a7cde
--- /dev/null
+++ b/w6/Swimmable.java
@@ -0,0 +1,5 @@
+package Sound;
+
+public interface Swimmable {
+    public abstract void swim();
+}