有關現在完成式既野想問問

When Chan said to Mary=He said that;
The present perfect tense;-have removed;
Present perfect denotes present results of past actions.
Note that by, since and for are used.
We use "since" when we refer to a point of time in the past and "for" when we refer to a period of time.
Hence:-----I have removed obstacles from ABC Tunnel by 2pm
----I have removed obstacles from ABC Tunnel since 1 pm for 2 hrs already.(completion)
----I have removed obstacles from ABC Tunnel since 1 pm for 2 hrs even though it is 4 by now.
----The verbs denote actions that are completed recently.

2014-10-04 17:36:41 補充：
Amendment:-Sorry that (2-1=1)hr. eg:-An interval is a period of time between two states.eg:-Obstacles removed from ABC Tunnel after an interval of one hour.

2014-10-10 10:22:38 補充：
To Godfrey:-Thanks for the encouragement.The posting "Chan"asked six times.He has got a real hang-up about his tense, being disagreed to his English Grammar or achieved anything else to post !

"I have removed obstacles from ABC Tunnel."
I said to Mary , "I had already removed the obstacles from the ABC Tunnel."

I removed the obstacles from ABC Tunnel from 1- 2 this afternoon.

噢，謝謝你 Godfrey。

我大意了～
為免誤導他人，讓我先刪除～

Thanks!
☆ヾ(◕‿◕)ノ

知足常樂 ( 知識長 ):

對不起, 恐怕我要說第二句是錯

“I have already removed obstacles from ABC Tunnel since 2 p.m.”
since 2 p.m. 解 "自 2 p.m. 以後"
不同 "by 2 p.m. "

這動作(移走障礙物) 在 2 p.m. 已經完成,
“remove“ 是 action verb, 不是 “state” verb.

2014-10-04 01:13:13 補充：
You use “since” to say that something has been the case from a particular time in the past until now.

ABC Tunnel has been passable since 2 p.m.
passable (adj.) = 可通行的

We have been waiting here since 2 p.m. (現在仍然在等)

2014-10-10 02:34:26 補充：
發問者 has got a real hang-up about "tense".
Only TOMING88 can cure him/her of all the hang-ups.
不知道發問者使用不同的姓名問過 tenses 多少次?