android中Activity的singletask模式弹出栈的问题

07-14 17:48:53.218: E/First(8272): onDestroy
 07-14 17:48:53.226: E/Second(8272): onDestroy
 07-14 17:48:53.226: E/Third(8272): onPause
 07-14 17:48:53.250: E/MAIN(8272): onRestart
 07-14 17:48:53.250: E/MAIN(8272): onStart
 07-14 17:48:53.250: E/MAIN(8272): onResume
 07-14 17:48:53.335: E/Third(8272): onStop
 07-14 17:48:53.335: E/Third(8272): onDestroy

Main是singletask启动模式
顺序是Main->First->Second->Third->Main

再次启动Main把上面的activity全部弹出，按照栈先进后出的结构，不是应该从Third开始到First，怎么是反过来的。