The Center <has run> <has been running> successfully for many years.

[Michaelll]

It depends on the sentence and the context. Some sentences might give you a stronger indication than others. I've said this above.

I was asking about those two sentences, 1b and 2b.

Let me clarify: neither the perfect simple form nor the perfect continuous form (in that sentence) put more or less emphasis on whether the action 1) has ceased, 2) is still going on, 3) will continue, correct? = Neither of them tell us whether the action is finished or not, even if it's the perfect simple and even if Tarheel says 2b (the perfect continuous) strongly suggests to him that the action is still going on, correct?

1b. All day, the police have stopped motorists to question them about the accident.
2b. All day, the police have been stopping motorists to question them about the accident.

 

[Tarheel]

I don't think I've ever heard of perfect continuous before.

 

[Michaelll]

A: Dr. Fletcher put this point across very differently a couple of years ago.
B: I don't think so. He's given the same lecture for the last ten years, without changing a word of his script.

A: Dr. Fletcher needs to update a few points in his standard lecture.
B: Yes, he's been giving the same lecture for the last ten years. He really needs to do something about it.

No. Neither of them, by themselves, mean that he's going to stop giving lectures.

What made you choose the perfect continuous over the perfect simple in one of the two, and the perfect simple over the perfect continuous in the other? I don't see this difference, I'd probably use the perfect continuous in both.

I once asked a British friend of mine, who taught English for four years in Minsk (now he's in England), what's the difference between the perfect simple and the perfect continuous when expressing duration up to now, and what's the difference between the past simple and the past continuous when expressing duration in the past, and he said that they are all fine (with action verbs), it's just that the perfect continuous is more common if it's until now, and the past simple is much more common if it's in the past. That looks like a reasonable, valid yet simple explanation.

I've been doing it for five years (since 2018). - more common
I've done it for five years (since 2018).

I was doing it for six years (from 2009 till 2015).
I did it for six years (from 2009 till 2015). - much more common

 

[Barque]

What made you choose the perfect continuous over the perfect simple in one of the two, and the perfect simple over the perfect continuous in the other?

The context.

and he said that they are all fine (with action verbs), it's just that the perfect continuous is more common if it's until now, and the past simple is much more common if it's in the past. That looks like a reasonable, valid yet simple explanation.

Yes, it sounds reasonable but the point I'm making is that there's no rule. This explanation may not always be valid.

 

[5jj]

In some languages, tenses and/or aspects can indicate the onset or cessation of a situation. This is not the case in English where onset and cessation are indicated by the inherent meaning of the verb.

 

[Skrej]

Thanks. Then, why do you think he claims that 1c and 1e are "also possible"?

For the record, 1c and 1e don't bother me at all. I imagine I've used them in a similar context before myself.

 

[Michaelll]

For the record, 1c and 1e don't bother me at all. I imagine I've used them in a similar context before myself.

Thank you! Very interesting, Skrej! Do you consider them as meaning almost the same thing?

1c. I have read this book on astrophysics for hours and I'm still only on page six.
2c. I have been reading this book on astrophysics for hours and I'm still only on page six.

 

[Tarheel]

Thank you! Very interesting, Skrej! Do you consider them as meaning almost the same thing?

1c. I have read this book on astrophysics for hours and I'm still only on page six.
2c. I have been reading this book on astrophysics for hours and I'm still only on page six.

I would only use the second one.

 

[emsr2d2]

Thank you! Very interesting, Skrej! Do you consider them as meaning almost the same thing?

1c. I have read this book on astrophysics for hours and I'm still only on page six.
2c. I have been reading this book on astrophysics for hours and I'm still only on page six.

Only the present perfect continuous works because it's clear from the final clause that you're still reading the book. If you read the book for several hours at some point in the past, you would use the simple past.

I read this book ... for [number] hours yesterday/last night/last week/in February.

 

[jutfrank]

He claims that both the present perfect and the present perfect continuous are possible in all of these sentences. Is it true? Are the present perfect options also possible in those sentences?

Yes, of course. You think he's got it wrong?!

As for me, I'd think they're all crying out for the continuous form.

Right. But that doesn't make the present perfect simple version not possible, does it?

You're thinking too much about what is 'possible'. Teachers and writers often say that an alternative form is 'possible' because they don't want to be too prescriptive. In all of the sentences from post #1, the continuous form is the one you should focus on. This is the first and main form given in the answer key. You must realise that those sentences were written specifically as examples of the present perfect continuous.

 

[Michaelll]

Yes, of course. You think he's got it wrong?!

No, I was just asking.

Only the present perfect continuous works because it's clear from the final clause that you're still reading the book. If you read the book for several hours at some point in the past, you would use the simple past.

I read this book ... for [number] hours yesterday/last night/last week/in February.

For some reason, Martin Hewings wrote that both are possible.

Looks like if you're still doing something, - use the perfect continuous. But, at the same time Barque wrote in #11 that neither the perfect simple version of the following sentence nor the perfect continuous one says whether the action has ceased or not. That's ... strange.

1b. All day, the police have stopped motorists to question them about the accident.
2b. All day, the police have been stopping motorists to question them about the accident.

 

[Michaelll]

If you read the book for several hours at some point in the past, you would use the simple past.

I read this book ... for [number] hours yesterday/last night/last week/in February.

To be honest, I just can't understand why some of you (not all of you) consider 1s not working...
If we can just say "I read this book for [number of hours] yesterday" - we don't need to use the continuous here "I was reading this book for [number of hours] yesterday", then why in the perfect aspect would we need the continuous instead of the simple? I just can't get it.

• (simple) I read this book ... for [number] hours yesterday. - fine
• (continuous) I was reading this book ... for [number] hours yesterday. - unnecessary
  
  
• (simple) I've read this book ... for [number] hours. - doesn't work (as some say)
• (continuous) I've been reading this book ... for [number] hours. - fine

I've been suffering trying to find logic in this for a long time.

 

[Tarheel]

@Michaelll Two things. One, do you know what "claim" means? Two, didn't we talk about this before?

 

[Barque]

The phrase "I've read this book" doesn't go with "for X hours", because "I've read this book" implies a completed action. "For X hours" suggests it isn't complete.

This works with "read a book". It may not be true for every verb/action. "Read a book" implies having read the whole book.

If you say "I've talked about this for three hours", that's different, though the structure is the same. "Talked about this for three hours" doesn't imply completion like "read a book", because you might keep talking about it for longer. That's just how it is. That's why I keep harping on context.

I've been suffering trying to find logic in this for a long time.

Don't try to look for logic. English isn't a logical language. Sometimes you just have to try and learn what's customary.

Every sentence is different. Even if they're exactly the same structure, they may not work the same way.

 

[Barque]

In the Indian languages I speak, the word "read" (past tense of "read") can also be used for "was reading". That's not so in English. Maybe that's what's causing you difficulty.

 

[jutfrank]

Michaelll, try to focus on what the book is trying to teaching you. The sentence you should be thinking about is this:

I have been reading this book on astrophysics for hours and I'm still only on page six.

I can only repeat what I've said before: This sentence was written specifically to help you understand how and when to use the present perfect continuous. Why do you insist on trying to change the aspect? If you want to study examples of the present perfect simple, then find other sentences. Using the same context, where two sentences differ only by the aspect, more often serves to confuse than to discriminate difference in meaning.

If it seems like the members here (and Mr Hewings) are disagreeing with each other, it is only on the point of what 'possible' and 'doesn't work' mean. There is no logic that you're missing. Stop thinking in terms of what's correct or incorrect and start thinking in terms of which sentence works better to emphasise what the speaker wants to emphasise. It seems to me that you do have a pretty good grasp of this grammar.