with error message :
Error: The tool was unable to install Application Server Role, Web Server (IIS) Role.
Error: Startup task doesn't exist. This is not a continuation after a restart.
after try out all the solution at internet but at last found out the root cause is :Windows Server 2012 R2 need to use sharepoint 2013 with SP1 only can run the prerequisites tools.
https://support.microsoft.com/en-us/kb/2891274?wa=wsignin1.0
*ha ha..first time deployment at windows 2012 R2 , learnt the lesson here