And I will use an example about my family

October, November, December, these are months when the weather turns cold and rainy and possibly snowy

At least, here in New England

In short, this is a time when people get sick

They get colds, they get the flu

My family has visited the doctor several times already

Why did I say, “Has visited”?

Because it’s still December

This period of time is not over yet

It’s incomplete, it’s unfinished

So to talk about an unfinished period of time, we can use the present perfect

There may be more visits to the doctor within this period of time

Once, again, the second reason for using the present perfect to express an unfinished period of time

The action likely happened repeatedly in the past

And the present perfect suggests that the action may happen again in the future

Before we consider the two examples below

Let’s look at the time line

The period and question began in the past, continue to the present and possibly existent to the future

It’s an unopened and unfinished period of time

First example, My family has visited the doctor several times already

The word “visit” in the past and there is maybe more in the future

Second example, The topic has been requested many times

The word “request” for the topic in the past

And there is maybe more requests in the future

And if there are i'll tell the viewers to watch the lesson

Sometimes it’s easier to understand one verb tense when you contrast it with another

I said that “My family has visited the doctor several times already”

The year is not over yet

There are a few more weeks before the end of the year

So there may be more visits to the doctor

It’s an unfinished period of time

But what about the last year 2007?

2007 is over and done with

It’s a finished... It’s a complete period of time

So I can say that last year we only went to the doctor two times

Went, we went to the doctor two times in 2007

2008?

We’ve visited the doctor several times already, “have visited” because 2008 is not over yet

So when we contrast the two tenses, we see that the present perfect expresses an unfinished or open period of time

The simple past expresses a finished or closed period of time

Now try again to understand the difference through the two examples using the present perfect

My family has visited the doctor several times already this year

This year is 2008

It’s not over

And with the simple past, My family visited the doctor only two times in 2007

2007 is a closed period of time

Now let’s me tell you about a third reason why we might use the present perfect

And I’ll use my work as an example

Some of you may know that I don’t just post videos here on Youtube

I write material for English language learners and for teachers of English as a second or foreign language

I’ve written several textbooks – a few in Russia and some here in the United States

Now why did I say “I’ve written some textbooks?"

Well, because it’s not really important for me for me to tell you the dates of publication

I said “I’ve written” because I’m talking about the general past – an unspecified past

I don’t need to be specific about the times that I wrote these books

I’m just telling you that these are things that I did in the past

I’ve written textbooks

I can also add those that the statement implies

That there is a hope I will write more

It’s similar to the sentence “My family has visited the doctor several times already”

Just as there may be more visits to the doctor

There are maybe more textbooks in the future I hope

Again, a third reason why we may use the present perfect is to talk about general experience in the past or past actions at unnamed or unspecified times

Consider the two examples

In both cases, I' m speaking in general about my professional experience

The first “I’ve written some textbooks”

The second “I’ve taught private and group classes”

Now, do you need to know when exactly I wrote the book

Or when exactly I taught the classes?

No, you don’t

So in the present perfect times and dates are unspecified usually because they are not important but they can also be unknown

Now, I'd like of the third reason

Let’s make another contrast between the present perfect and the simple past

The present perfect can express the general past

"I’ve written some textbooks” when exactly the date isn’t specified

With the simple past we name the specific, “My first book came out in 2000”

So, should  we have the specific date

And we can show a point or time line

We need to use the simple past not the present perfect

Exercise: choose the best verb tense to complete the statement: the present perfect or the simple past

Number one read the statement to yourself and then I’ll tell you the answer

Answer “ I have been or I’ve been to Siberia two times. I’d love to return one day with my husband and children”

I said “I’ve been” because there are suggestions of future visit

I don’t think the simple past is incorrect

But I think that the present perfect is the best choice here

Number two, answer, “I won’t be able to return to my hometown of Pittsburgh before the end of the year, but I saw my parents back in May and again in October"

The only choice here is the simple past. “ I saw”

First of all, we have the specified mention of time in May in October

Second , although the year is not uncompleted at the time I’m speaking

This is no suggestion of additional visits

Number three. Answer, “My husband and I have traveled abroad"

"We were in Belgium in 2001 and we loved it"

"We talk about going back there one day”

The first sentence uses the present perfect

It’s the better choice because we’re speaking about a shared general past experience

Also at the end of statement there is suggestion of future travel

In the second sentence, We have specific date mention in 2001

2001 is a finished period of time so we must use the simple past

I hope you’ve understood everything so far

Please, go on to the next part of this lessons