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.

MENGGUNAKAN SIMPLE PAST vs. PRESENT PERFECT

SIMPLE PAST: (a)      I finished my work two hours ago. PRESENT PERFECT: (b)     I have already* finished my work.	In (a): I finished my work at a specified time in the past (two hours ago). In (b): I finished my work at an unspecified time in the past (sometime before now). The simple past expresses an activity that occurred at a specific time (or times) in the past, as in (a) and (c).  The present perfect expresses an activity that occured at an specified time (or times) in the past, as in (b) and (d).
SIMPLE PAST: (c)      I was in Europe last year/three years ago/in 1989/in 195 and 1989/when I was ten years old. PRESENT PERFECT: (d)     I have been in Europe many times/several times/a couple of times/once/(no mention of time).

*Already has the same usual placement as frequency adverbs. Already means “before”.

ARTI-ARTI DARI PRESENT PERFECT

(a)      Jim has already eaten lunch. (b)      Ann hasn’t eaten lunch yet. (c)      Have you ever eaten at that rastaurant? (d)     I’ve never eaten here.	The present perfect expresses activities or situations that occurred (or did not occur) “before now,” at some unspecified time in the past.*
(e)      Pete has eaten at that restaurant many times. (f)       I’ve been to that theater five or six times. (g)      I’ve had three tests so far this week.	The present perfect expresses activities that were repeated several or many times in the past. The exact times are unspecified.
(h)      Erica has lived in this city since 1989. (i)        I have known Ben for ten years. (j)        We’ve been in class since ten o’clock this morning.	When the present perfect is used with since or for, it expresses situations that began in the past and continue to the present.

*If the exact time is specified, the simple past tense is used.

SPECIFIED TIME: Jim ate lunch at 12:00/two hours ago/yesterday.

UNSPECIFIED TIME: Jim has already eaten lunch. (at some unspecified time before now)

BENTUK-BENTUK PRESENT PERFECT

STATEMENT: HAVE/HAS + PAST PARTICIPLE (a)      I have finished my work. (b)     The students have finished Chapter 5. (c)      Jim has eaten lunch.	The basic form of the present perfect: have or has + the past participle. Use have with I, you, we, they, or plural noun (e.g., students). Use has with she, he, it, or singular noun (e.g., Jim). With pronouns, have is contracted to apostrophe + ve (‘ve) and has to apostrophe + s (‘s).
(d)     I’ve/You’ve/We’ve/They’ve eaten lunch. (e)      She’s/He’s eaten lunch. (f)      It’s been cold for the last three days.
NEGATIVE: HAVE/HAS + NOT + PAST PARTICIPLE (g)     I have not (haven’t) finished my work. (h)     Ann has not (hasn’t) eaten lunch.	have + not = haven’t has + not = hasn’t
QUESTION: HAVE/HAS + SUBJECT + PAST PARTICIPLE (i)       Have you finished your work? (j)       Has Jim eaten lunch? (k)     How long have you lived here?	In a question, the helping verb (have or has) precedes the subject.
(l)       A: Have you seen that movie? B: Yes, I have. OR: No, I haven’t. (m)   A: Has Jim eaten lunch? B: Yes, she has. OR: No, she hasn’t.	The helping verb (have or has) is used in a short answer to a yes/no question. The helping verb in the short answer is not contracted with the pronoun.

PAST PARTICIPLE

	SIMPLE FORM	SIMPLE PAST	PAST PARTICIPLE	The past participle is one of the principal parts of a verb. The past participle is used in the PRESENT PERFECT tense and the PAST PERFECT tense. The past participle is also used in the passive. The past participle of regular verbs is the same as the simple past form: both end in –ed.
REGULAR VERBS	finish stop wait	finished stopped waited	finished stopped waited
IRREGULAR VERBS	see make put	saw made put	seen made put