PRESENT PERFECT

The present perfect expresses the idea that something happened (or never happened) before now, at an unspecified time in the past. The exact time it happened is not important.

If there is a specific mention of time, the simple past is used: they moved into a new apartment last month.

Notice: the adverbs ever, never, already, yet, still and just are frequently used with the present perfect.

EXAMPLES:

a)       They have moved into a new apartment.

b)       Have you ever visited México?

c)       I have never seen snow

d)       I have already seen that movie.

e)       Jack hasn´t seen it yet.

f)        Ann started a letter to her parents last week, but she still hasn´t finished it.

g)       Alex feels bad. He has just heard some bad news.

h)       We have had four tests so far this semester.

i)         I have written my wife a letter every other day for the last two weeks.

j)        I have met many people since I came here in June.

k)       I have flown on an airplane many times.

l)         I have been here since 7 o´clock.

m)     We have been here for two weeks.

n)       I have had this same pair of shoes for three years.

o)       I have liked cowboy movies ever since I was a child.

p)       I have known him for many years.

The present perfect also expresses the repetition of an activity before now. The exact time of each repetition is not important.

Notice in h: so far is frequently used with the present perfect.

The present perfect, when used with for or since, also expresses a situation that began in the past and continues to the present.

Notice: the difference between since and for:

Since + a particular time

For+ a duration of time