現在完成式既問題詢問

I have thrown away (=out) boxes since this morning.

(2)I have just thrown away boxes for the last time !
---I have already thrown away the boxes for the last time !

2015-04-06 20:55:48 補充：
for 15 boxes.

無問題 ~~ 而如果想強調 "一次過", 就加多少少

I have trown away my fifteen boxes at the same time.

否則已經 ok