關於現在完成式既問題

Perfect(grammar) connected with the form of a verb that consists of part of the verb have with the past participle of the main verb, used to express actions completed by the presenrt or a particular point in the past or future. eg:-I have collected is the present perfect tense of the verb "to collect", "I had collected" is the past perfect tense and "I will have collected" is the future perfect.To describe should be:-eg:-sick=adj;--and went sick of it as a hobby.
--------------and get sick of it as it becomes a hobby.
--------------and feel sick.
--------------and feel sick of it at 8:00:00.
--------------and make myself sick.
--------------and make myself sick of it at 8:00:00.

I have collected stamps since 1/1/2013 but decided to give it up since18/12/2013

or

I have collected stamps since 1/1/2013 but decided to give it up on 18/12/2013

我個人認為如果你有提到個時間 就唔可以用present perfect tense
但如果你冇講既 咁就得啦

注意: 你用present perfect tense要同儀家所發生既事有關係呀!!

( just for suggestion)

i think yes .