Student or Learner
"could have+pp" is usually either counterfactual result in conditionals or presumption in the past. But this seems to be a factual expression like "had been able to". Is this usage common or exceptional?
ex)We sometimes encounter students who come to our offices and ask how they could have worked so hard but still failed our tests. They usually tell us that they read and reread the textbook and their class notes, and that they thought they understood everything well by the time of the exam...
Your example phrases containing how could you have shows me about the past usage of "could have p.p", but I don't know why I feel it's for past perfect usage. I rarely have seen "could have p.p" as a factual thing. It was either presumption or counterfactual result. Then, what do you think is the difference between the following two?
1. He says he could have finished his homework- I think this is counterfactual result, He didn't finish it
2. He says he could finish his homework - He finished it.(maybe "was able to" fits better)
1. He said he could have finished his homework- He had finished - maybe possible
2. He said he had been able to finish his homework - He had finished
O.K. Let's change them into the direct speech.
1. He says, "(If I had had enough time,) I could have finished my homework."
2. He says, "I was able to (or managed to) finish my homework." (Yes, I agree with you. 'was able to/managed to' fits better.)
3. He said, "(If I had had enough time,) I could have finished my homework."
4. He said, "I was able to/have been able to finish my homework."
Do you agree?
Last edited by tzfujimino; 21-Jul-2012 at 07:22.
No, what I meant was not the interpretation of each, but "could have pp" is rarely used as a factual thing if you compare each couple.
If I understand you correctly (your query about the "factual thing"), the only usage I can think of is when it (could+have+p.p) is used with "how".
"How could you possibly have done...?" - I think it is used to express the speaker's 'disbelief' or 'doubt' or 'surprise'...etc.
Do you see what I mean?
Last edited by tzfujimino; 21-Jul-2012 at 09:08.
I once asked a native speaker teacher about this "could have pp", and he said it's always presumption or counterfactual result, not a factual description. So I think the following is either a mistake or an exceptional usage of factual things.
Anyway, your explanation of "how could you have p.p?" is awesome. I have forgot it's a doubt or disbelief, so I got quite refreshed about it.
ex)how they could have worked so
Thinking deeply about it, I can't help but conclude that what tzfu said is right in relation to "doubt about the past".
"could" or "could have p.p" has the nuance of "imaginary or counterfactual result, so the students doubted the result as falsehood even though they knew it was true.