diff --git a/ch6-cloud/ch6-08-lock.md b/ch6-cloud/ch6-08-lock.md
index a2c7499..b24715b 100644
--- a/ch6-cloud/ch6-08-lock.md
+++ b/ch6-cloud/ch6-08-lock.md
@@ -226,48 +226,48 @@ unlock success!
 package main
 
 import (
-	"fmt"
-	"log"
-	"os"
-	"time"
+    "fmt"
+    "log"
+    "os"
+    "time"
 
-	"github.com/nladuo/go-zk-lock"
+    "github.com/nladuo/go-zk-lock"
 )
 
 var (
-	hosts         []string      = []string{"127.0.0.1:2181"} // the zookeeper hosts
-	basePath      string        = "/locker"                  //the application znode path
-	lockerTimeout time.Duration = 5 * time.Second            // the maximum time for a locker waiting
-	zkTimeOut     time.Duration = 20 * time.Second           // the zk connection timeout
+    hosts         []string      = []string{"127.0.0.1:2181"} // the zookeeper hosts
+    basePath      string        = "/locker"                  //the application znode path
+    lockerTimeout time.Duration = 5 * time.Second            // the maximum time for a locker waiting
+    zkTimeOut     time.Duration = 20 * time.Second           // the zk connection timeout
 )
 
 func main() {
-	end := make(chan byte)
-	err := DLocker.EstablishZkConn(hosts, zkTimeOut)
-	defer DLocker.CloseZkConn()
-	if err != nil {
-		fmt.Println(err)
-		os.Exit(1)
-	}
+    end := make(chan byte)
+    err := DLocker.EstablishZkConn(hosts, zkTimeOut)
+    defer DLocker.CloseZkConn()
+    if err != nil {
+        fmt.Println(err)
+        os.Exit(1)
+    }
 
-	//concurrent test lock and unlock
-	for i := 0; i < 100; i++ {
-		go run(i)
-	}
-	<-end
+    //concurrent test lock and unlock
+    for i := 0; i < 100; i++ {
+        go run(i)
+    }
+    <-end
 }
 
 func run(i int) {
-	locker := DLocker.NewLocker(basePath, lockerTimeout)
-	for {
-		locker.Lock() // like mutex.Lock()
-		fmt.Println("gorountine", i, ": get lock")
-		//do something of which time not excceed lockerTimeout
-		fmt.Println("gorountine", i, ": unlock")
-		if !locker.Unlock() { // like mutex.Unlock(), return false when zookeeper connection error or locker timeout
-			log.Println("gorountine", i, ": unlock failed")
-		}
-	}
+    locker := DLocker.NewLocker(basePath, lockerTimeout)
+    for {
+        locker.Lock() // like mutex.Lock()
+        fmt.Println("gorountine", i, ": get lock")
+        //do something of which time not excceed lockerTimeout
+        fmt.Println("gorountine", i, ": unlock")
+        if !locker.Unlock() { // like mutex.Unlock(), return false when zookeeper connection error or locker timeout
+            log.Println("gorountine", i, ": unlock failed")
+        }
+    }
 }
 
 ```