MENGGUNAKAN SINCE AND FOR

SINCE	(a) I have been here	since eight o’clock. since Tuesday. since May. since 1989. since January 3, 1988. since the beginning of the semester. since yesterday. since last month.		Since is followed by the mention of a spesific point in time: an hour, a day, a month, a year, etc. Since expresses the idea that an activity began at a specific time in the past and continues to the present. The present perfect also expresses the idea that an activity began in the past and continues to the present.
	(b) INCORRECT: I am living here since May. (c) INCORRECT: I live here since May. INCORRECT: I am here since May. (d) INCORRECT: I lived here since May. INCORRECT: I was here since May. (e) CORRECT: I have lived here since May. CORRECT: I have been here since May. CORRECT: I have been living here since May.			The present perfect is used in sentences with since. In (b): The present progressive is NOT used. In (c): The simple present is NOT used. In (d): The simple past is NOT used.
	MAIN CLAUSE (present perfect) (f) I have lived here (g) Al has met many people		SINCE CLAUSE (simple past) since I was a child. since he came here.	Since may also introduce a time clause (i.e., a subject and verb many follow since). Notice in the examples: The present perfect is used in the main clause; the simple past is used in the “since clause”.
FOR	(h) I have been here		for ten minutes. for two hours. for five days. for about three weeks. for almost six months. for many years. for a long time.	For is followed by the mention of a length ot time: two minutes, three hours, four days, five weeks, etc. Note: If the noun ends in –s (hours, days, weeks, etc.), use for in the time expression, not since.
	(i) I have lived here for two years. I moved here two years ago, and I still live here. (j) I lived in Chicago for two years. I don’t live in Chicago now.			In (i): The use of the present perfect in a sentence with for + a length of time means that the action began in the past and continues to the present. In (j): The use of the simple past means that he action began and ended in the past.