diff --git a/day09/src/com/inmind/extends_td05/A.java b/day09/src/com/inmind/extends_td05/A.java
new file mode 100644
index 0000000..e524a3c
--- /dev/null
+++ b/day09/src/com/inmind/extends_td05/A.java
@@ -0,0 +1,4 @@
+package com.inmind.extends_td05;
+//父类
+public class A {
+}
diff --git a/day09/src/com/inmind/extends_td05/B.java b/day09/src/com/inmind/extends_td05/B.java
new file mode 100644
index 0000000..0b435a9
--- /dev/null
+++ b/day09/src/com/inmind/extends_td05/B.java
@@ -0,0 +1,4 @@
+package com.inmind.extends_td05;
+
+public class B extends A{
+}
diff --git a/day09/src/com/inmind/extends_td05/C.java b/day09/src/com/inmind/extends_td05/C.java
new file mode 100644
index 0000000..5692f75
--- /dev/null
+++ b/day09/src/com/inmind/extends_td05/C.java
@@ -0,0 +1,4 @@
+package com.inmind.extends_td05;
+//父类
+public class C extends B{
+}
diff --git a/day09/src/com/inmind/extends_td05/D.java b/day09/src/com/inmind/extends_td05/D.java
new file mode 100644
index 0000000..6eb7d85
--- /dev/null
+++ b/day09/src/com/inmind/extends_td05/D.java
@@ -0,0 +1,4 @@
+package com.inmind.extends_td05;
+
+public class D extends C{
+}
diff --git a/day09/src/com/inmind/extends_td05/Demo07.java b/day09/src/com/inmind/extends_td05/Demo07.java
new file mode 100644
index 0000000..650e981
--- /dev/null
+++ b/day09/src/com/inmind/extends_td05/Demo07.java
@@ -0,0 +1,10 @@
+package com.inmind.extends_td05;
+/*
+继承的特点-单继承-多层继承
+注意：java中所有的类，都直接或间接继承Object
+ */
+public class Demo07 {
+    public static void main(String[] args) {
+        D d = new D();
+    }
+}