diff --git a/w6/Animal.java b/w6/Animal.java
new file mode 100644
index 0000000..68bf39c
--- /dev/null
+++ b/w6/Animal.java
@@ -0,0 +1,3 @@
+public abstract class Animal {
+    public abstract void makeSound ();
+}
diff --git a/w6/Cat.java b/w6/Cat.java
new file mode 100644
index 0000000..b819b24
--- /dev/null
+++ b/w6/Cat.java
@@ -0,0 +1,6 @@
+public class Cat extends Animal{
+    @Override
+    public void makeSound() {
+        System.out.println("猫：喵喵喵");
+    }
+}
diff --git a/w6/Dog.java b/w6/Dog.java
new file mode 100644
index 0000000..90455cf
--- /dev/null
+++ b/w6/Dog.java
@@ -0,0 +1,11 @@
+public class Dog extends Animal implements Swimmable{
+    @Override
+    public void makeSound() {
+        System.out.println("狗：汪汪汪");
+    }
+
+    @Override
+    public void swim() {
+        System.out.println("狗会游泳");
+    }
+}
diff --git a/w6/Main.java b/w6/Main.java
new file mode 100644
index 0000000..176ce14
--- /dev/null
+++ b/w6/Main.java
@@ -0,0 +1,20 @@
+public class Main {
+    public static void main(String[] args){
+        Animal dog = new Dog();
+        Animal cat = new Cat();
+
+        System.out.println("动物叫声");
+        dog.makeSound();
+        cat.makeSound();
+
+        System.out.println("是否会游泳");
+        if (dog instanceof Swimmable){
+            ((Swimmable) dog).swim();
+        }
+        if (cat instanceof Swimmable){
+            ((Swimmable) cat).swim();
+        } else {
+            System.out.println("猫不会游泳");
+        }
+    }
+}
diff --git a/w6/Swimmable.java b/w6/Swimmable.java
new file mode 100644
index 0000000..d3b896f
--- /dev/null
+++ b/w6/Swimmable.java
@@ -0,0 +1,3 @@
+public interface Swimmable {
+    void swim();
+}