有關英文時式問題請教大家

圖片參考：https://s.yimg.com/lo/api/res/1.2/ZQit8r6YM3UMER1bF6V.OQ--/YXBwaWQ9dHdhbnN3ZXJzO3E9ODU-/http://i.imgur.com/ZH9B85L.gif

您好～

我們看一看時間線：
13:00 - 13:25：Tommy 寫始寫一封信
13:25 - 13:35：休息
13:35 - 13:55：繼續寫信
13:55：寫信結束
14:05：講 "Tommy just wrote letters this afternoon."

時態方面
無問題。
因為說本句的時候，所描述的動作（寫信）已經結束。

用字方面
有問題。
(1) Tommy 只寫了一封信，所以不應用 letters，而應該用 a letter。
(2) 說話的時候下午嘗未過去，所以用 this afternoon 不是太好。

你可以考慮改寫為：
Tommy just finished writing a letter.
Tommy just wrote a letter.


圖片參考：https://s.yimg.com/lo/api/res/1.2/WNPMvOsZxQ9t6JJX7IWl7A--/YXBwaWQ9dHdhbnN3ZXJzO3E9ODU-/http://www.stormmediagroup.com/upload/frontend/de64aa90-6c17-431f-bf5d-97c0a71ad961/23acafbd-f31c-4516-a55a-187c64715418.gif

Tommy who started to write the letter at one o'clock in this afternoon and then he has been writing intermittently till finished at one o'clock and fifty five minutes..

Tommy has wrote the letter already.

Tense used to show the time of the action or state :-
For the time schedules:-
(1:00-1;25)pm--to write a letter
(1:25-1:35)pm=10 min.--take a break
(1:35-1:55)pm--continue to write the letter
2:05 pm -speaking time
eg:-Tommy has written a letter this afternoon,finishing (gerund of a verb) at 1:55 pm.
So now all the time involved in this case on the matter of writing , despite a 10 min's break, were (1:30-1:55)pm;
eg:-Tom has written a letter this afternoon.
For an action just concluded when the resulting writing state is still present is still the present perfect tense;-
eg:-Tom has written a letter this afternoon.