1. Differences

2.  Auxiliary
have+ past participle:
Ex: I have done my homework.
 QUESTIONS: Inversion:
Ex.: Have you done your homework yet?
 NEGATIVE: Have+not (haven’t/hasn’t):
Ex.: No, I haven’t done my homework yet.

3.  Generally speaking, to talk about something that
started in the past and continues in the present or
has consequences in the present.
 For past experiences (often with ever/ never, which
always go before the main verb):
Ex.: Have you ever cheated in an exam?
Ex.: I haven’t been to London.
 With yet (at the end of the sentence) and already
(before the main verb) for emphasis:
Ex.: I’ve already done my homework.
Ex.: Have you done your homework yet?
Ex.: I haven’t done my homework yet.

4.  Unfinished states (non-action verbs) which
start in the past and are still true in the
present:
Ex.: We’ve been married for 50 years.
 Recent past actions, often with just (which
goes before the main verb)
Ex.: I’ve cut my finger. It’s bleeding.
(normally with consequences in the present)
Ex.: I’ve just finished my homework.

5.  How long: To ask about an unfinished period
of time (from the past until now):
Ex.: How long have you known each other?
 For:for a period of time:
Ex.: We’ve known each other for 15 years.
 Since:
for the starting point in the past:
Ex.: We’ve known each other since 2005/
since we were at school.

6.  Avoid Spanglish:
 SPANISH: Llevamos dos años casados/Nos
conocemos desde hace dos años.
 ENGLISH: We’ve been married for two
years/We’ve known each other for two years.
 Since cannot be used with ago. Ago is always
used with a past tense:
 Ex.: We got married five years ago, in 2007.

7.  The simple past is used for finished actions in the past, with no
connection to the present. We normally use a past time expression:
Ex: We went to London last summer/in 2011.
 BUT with no past expression:
Ex.: We’ve been to London twice (up to now, we could go back there
in the future).
 Simple past: always finished actions:
Ex.: We were married for 10 years (we aren’t married now BUT:
We’ve been married for 10 years (We are still married now).
 Simple past: I say when:
 Ex.: I cut my finger at work yesterday. BUT
 I’ve cut my finger (I don’t say when, we understand it’s recent).