diff --git a/README.md b/README.md
index 518114c..d00f366 100644
--- a/README.md
+++ b/README.md
@@ -24,7 +24,7 @@ Some examples are at `/cmd` folder.
 
 # Getting start
 After you install golang tools:
-- Run `go run cmd/ping/ping.go` to ping and list the Miaoscraft mc-server.  
+- Run `go run cmd/ping/ping.go localhost` to ping and list the Miaoscraft mc-server.  
 - Run `go run cmd/daze/daze.go` to join local server at *localhost:25565* as Steve on offline mode.
 
 See `/bot` folder to get more infomation about how to create your own robot.
\ No newline at end of file
diff --git a/bot/ingame.go b/bot/ingame.go
index d5be99d..d3fc566 100644
--- a/bot/ingame.go
+++ b/bot/ingame.go
@@ -124,7 +124,7 @@ func (c *Client) handlePacket(p pk.Packet) (disconnect bool, err error) {
 	case data.NamedSoundEffect:
 		err = handleNamedSoundEffect(c, p)
 	default:
-		
+
 		// fmt.Printf("ignore pack id %X\n", p.ID)
 	}
 	return
diff --git a/bot/world/entity/player/player.go b/bot/world/entity/player/player.go
index db141cd..54491c2 100644
--- a/bot/world/entity/player/player.go
+++ b/bot/world/entity/player/player.go
@@ -11,7 +11,7 @@ type Player struct {
 	Yaw, Pitch float32
 	OnGround   bool
 
-	HeldItem  int //拿着的物品栏位
+	HeldItem int //拿着的物品栏位
 
 	Health         float32 //血量
 	Food           int32   //饱食度
diff --git a/cmd/ping/ping.go b/cmd/ping/ping.go
index 11f45a4..ec38dd1 100644
--- a/cmd/ping/ping.go
+++ b/cmd/ping/ping.go
@@ -1,3 +1,4 @@
+// Useage: go run cmd/ping/ping.go localhost
 package main
 
 import (