Present perfect and Past simple

Most of the students, find difficult the circumstances of when it should be used either present perfect or past simple.
example:

Mark is looking for his wallet. He can't find it.
Mark has lost his wallet. (action, present perfect)

That means that he is not in possess of his wallet, at the time of speaking, now.


and a few minutes after..


Now Mark has found his wallet. He has it now.
Has he lost his wallet? No, he has found it.
Did he lose his wallet? Yes, he did.

He lost his wallet,            (before, present simple)
but now he has found it!  (now, present perfect)



The present perfect is a present tense. It always tells us about the situation now. The present simple tells us only about the the past, it doesn't tell anyting about the situation now.

This scheme represents most of the past tens, we have seen so far:

Note:

• Present perfect is used for new or recent happenings: I've just seen a nice advertisement on TV
• Past simple is used for things that are not recent or new: My grandfather grew up in Sardinia, then he moved to Italy when he was 35 years old.

Compare the examples:
- Who invented the first car?
- Do you know if the Europeans car manufacturers have invented some new eco-engine?

• Present perfect is used to give new information, but if we continue to talk about it, we normally use the past simple.

more examples:
- I've just cut my finger!
- Are you ok? I'll bring you a plaster.
- Yes please, take here the whole first Aid box.
- How did it happened?
- I cut myself with the new knife, is so sharped!

Do not forget, what we said in the previous lessons:

• Present perfect is not used when is refered to a finished time (yesterday, in 1980, yesterday, when i was a child): last weekend was soo cold.
• When in the sentence there is When or What time, it must be used the Past simple: what time did you get home last night?

more examples:
- It hasn't snowed yet this year.     (Present perfect)
- It didn't snow last year.               (Past simple)

- at breakfast time: Have you shaved this morning?         (Present perfect)
- at dinner: You didn't shave this morning, isn't?               (Past simple)

- I have never been in Tunisia.    (Present perfect)
- I was in Tunisia in 2005.           (Past simple)

Present perfect 2

Compare the examples:
I have lived in London for two years. (I live in London now.)
I lived in London for two years. (I don't live in London now.)







When we talk about a period of time that continues from the past until now, it is used the present perfect (have been / have done..)

examples:
- Have you ever driven a Ferrari?    (in your life)
- What a boring comedy! Is the most boring comedy I've ever seen!
- I've never been in Israel. Have you ever been there?
- I haven't seen you for a long time! 

The present perfect is commonly used with:
for a long time, recently, so far, in the last few week or days, since breakfast, today, this morning, this year, is the first time

In these examples the periods that we refer to, are not finished:



- Have you been on holiday this year? (is still this year)

- Have you shaved this morning?       (is still this morning)- So far, i haven't seen so much interest from you!
- David hasn't studied so much this term.
- Is the first time she has played guitar in front of so many people.
- Carla has never driven a car before.

Present Perfect

Matt is playing a videogame. He had to do some homework.
He has finished his homework, so now he can play the videogame.




Matt has finished his homework recently, but he doesn't say when exactly.

The present simple is have/has + past participle. The past participle often ends in -ed (finished, watched, decided, ..), but many verbs are irregular (forgotten, mistaken, been, seen,..)

When it's said that "something happened", this is usually new information:
examples:
- Someone has eaten my soup!
- Have you seen 'Gone with the Wind'?
- She has studied Japanese, Russian and English.

When there is a connection with now, thr action in the past has a result with now:
examples:
- She has worked in the bank for five years.
- We have had the same car for ten years.
- She gave me her number, but I have lost it!

We can use the present perfect with just, already and yet:
Just = a short time ago
I have just finished my homeworks.

Already = something has happened sooner than expected
I have already sent you the email, with the document you asked me.


Yet = the speaker is waiting for something to happen. 
Have you seen Mario yet?
He has finished her project, but she hasn't sent it to the costumer yet.
We only use the temporal adverb yet, in questions and negative sentences.