diff --git a/README.md b/README.md
index 36516b5..4db3602 100644
--- a/README.md
+++ b/README.md
@@ -2,3 +2,7 @@ CaptureNetworkState
 ===================
 
 using tcpdump capture the network state . implement in Android.
+
+the RTT is assosiate with [happen time] [tcp/ip flow] [rtt].
+and if want to see it , you may modify it in MainActivity.java in mainGather() method,
+and uncomment the system.out.println().