Present perfect and past simple


	Present perfect and past simple


				Bahito from Algeria asks: Could you please explain to me the exact difference between the uses of the present perfect and past simple tenses, especially when asking questions?


	Roger replies:

We use the present perfect when we are considering something that started in the past and which we want to connect with the present.

It may be something that started in the recent past, or it may have started a long time ago. Look at the following examples:

'I've lived in this small village all my life.' (i.e. up to the present and probably into the future too.)

'I haven't yet visited the capital city and I've only been to the provincial capital once.' (i.e. in my entire life)

'But I've just passed my driving test and I've bought a new car (both in the very recent past) and I intend to travel soon.'

In the affirmative, we often use the prepositions for or since with a time phrase and the adverbs just and already.

In the negative we often combine the present perfect with the adverbs never and yet. Look at the way they are used in the following and the preceding examples.

'She's worked as a doctor for the last twenty five years and has never been ill herself.'

'I've known Tom's sister since we were at school together.'

'You've already cleaned the house and prepared lunch and it's only eleven o'clock. Slow down!

Present perfect: interrogative

When we want to ask questions using the present perfect, we often use the adverbs ever and yet or use the How long...? construction.

For the interrogative, we must also remember to invert subject and verb. Study the following:

'Have you ever tried to swim in the North Sea?' 'No I never have. It's far too rough.'

li> 'Has the doctor called yet to see mother?' 'Yes, he's just been.'

'Have you finished your homework?' 'No, not yet. I still have maths to do.'

'How long have you had that coat?' 'Oh, for about two years now. It's not new.'

'How long have you been in Britain?' 'I've been here for two weeks already.

Past simple: affirmative and negative

We use the past simple when we want to refer to actions which were completed in the past. It is used with a wide variety of past time phrases or expressions in reply to the question When??, such as; earlier this morning, yesterday, last week, from April until June last year, in 1999, during the war, between 1985 and 1988, before we got married.

The negative is formed with the auxiliary verb didn't. Study the following examples:

'I saw Henry at the meeting this morning, but I didn't see Sue.'

'I bought a lot of language books when I was in London last week.'

'Over fifteen million people emigrated to the United States during the 19th century.'

'I didn't have time to finish the article before I left for work.

Notice that in the past participle in the present perfect, and in the affirmative in the past simple, regular verbs end in -ed, but notice also how many common irregular verbs there are in the above examples. The past simple is the standard tense used to describe actions which follow each other when telling a story. But in the following example notice how the present perfect is used:

'I came home late last night. Fred was in the kitchen but he didn't say anything. He just looked at me as if to say: 'I know where you have been.' We ate our supper in silence and then we went to bed.'

Past simple: interrogative

In the interrogative, we must always remember to use the auxiliary verb did with normal inversion. It is always associated with the When...? question and may be used with a wide variety of other question forms too. Study the following examples:

It is early evening in Henry's home in the country.

Henry:	Hello Sheila. I didn't expect to see you here.
Sheila:	Oh, I've been here for quite a while.
Henry:	When did you arrive?
Sheila:	Just after lunch.
Henry:	Did Patrick pick you up from the station?
Sheila:	No, it was a nice day so I walked.
Henry:	Have you eaten anything since you've been here?
Sheila:	Yes, I had afternoon tea with the girls.
Henry:	What did you think of Penny?
Sheila:	She's grown up a lot since I last saw her.
Henry:	And how did you find Rebecca?
Sheila:	She didn't join us. I haven't seen her yet.

Now see if you can write a dialogue combining the past simple and present perfect.