diff --git a/README.md b/README.md
index c4cd6c2..8406363 100644
--- a/README.md
+++ b/README.md
@@ -73,8 +73,9 @@ $ go get github.com/Tinywan/golang-tutorial
 ###  34 - 反射  
 ###  [35 - 读文件](/docs/golang_tutorial_35.md)  
 
-## 其他文档  
-
-* [如何编写Go代码](/docs/how_to_write_go_code.md)  
+## 文档  
+* [Go 零基础编程入门教程](http://go-courses.tinywan.com/_book/)
+* [Go 语言标准库](http://go-library.tinywan.com/_book/)
+* [如何编写 Go代码](/docs/how_to_write_go_code.md)  
 * [原文](https://golangbot.com/)  
 
diff --git a/demo/channel/demo01.go b/demo/channel/demo01.go
new file mode 100644
index 0000000..7905807
--- /dev/null
+++ b/demo/channel/demo01.go
@@ -0,0 +1,5 @@
+package main
+
+func main() {
+
+}
diff --git a/demo/point/demo.go b/demo/point/demo.go
index 4cc7303..cbc98f5 100644
--- a/demo/point/demo.go
+++ b/demo/point/demo.go
@@ -4,9 +4,16 @@ import (
 	"fmt"
 )
 
-func main(){
+func main() {
 	b := 255
 	var a = &b
-	fmt.Printf("Type of a is %T\n",a)
-	fmt.Println("address of b is",a)
-}
\ No newline at end of file
+	fmt.Printf("Type of a is %T\n", a)
+	fmt.Println("address of b is", a)
+
+	s := map[string]int{"age": 24}
+	var t map[string]string // 正确
+	t1 := map[string]string // 错误
+	fmt.Println(s)
+	fmt.Println(t)
+	fmt.Println(t1)
+}
diff --git a/demo/point/dmoe002.go b/demo/point/dmoe002.go
new file mode 100644
index 0000000..5660b48
--- /dev/null
+++ b/demo/point/dmoe002.go
@@ -0,0 +1,47 @@
+package main
+
+import (
+	"fmt"
+	"reflect"
+)
+
+// import (
+// 	"fmt"
+// ) go_basic_courses
+
+func main() {
+	// 声明一个集合字典，默认为空
+	a := 15
+	fmt.Println("address of b is ", a)
+	fmt.Println("address of b is ", &a)
+	m := map[string]int{}
+	fmt.Println("address of b i is ", m)
+	fmt.Printf("Type of a is %T\n", m)
+	fmt.Printf("m值是 %v \n", m == nil)
+	var dir map[string]string
+	fmt.Printf("dir字典的值是:   | %v \n", dir)
+	fmt.Printf("dir字典是否为nil | %v \n", dir == nil)
+	// nil map不能赋值,如果直接赋值会报错：“panic: assignment to entry in nil map”，下面语句将会报错
+	// dir["name"] = "Tinywan"
+
+	fmt.Println("----------------------------")
+	// 使用make函数进行初始化创建一个非nil的map
+	dir = make(map[string]string)
+	// map是引用类型，未初始化的是指向nil，初始化了以后应该就有自己的内存空间了，所以不是nil
+	fmt.Printf("dir字典的值是:   | %v \n", dir)
+	fmt.Printf("dir字典是否为nil | %v \n", dir == nil)
+
+	fmt.Println("----------------------------")
+	// make之后分配内存了,一旦分配了内存地址就不为空了,可以赋值了
+	dir["name"] = "Tinywan"
+	fmt.Printf("dir字典的键:值 |%v \n", dir)
+	fmt.Printf("dir字典的类型  |%v \n", reflect.TypeOf(dir))
+	fmt.Printf("name的值是     |%v \n", dir["name"])
+	// value, ok := s["ok"]
+	// if ok == nil {
+	// 	s := make(map[string]int)
+	// 	s["ok"] = 19
+	// 	fmt.Println(s["ok"])
+	// }
+	// fmt.Println(s["ok"])
+}