Use of Perfect Infinitive

[taruns1008]

1 He is understood to have left India for good last year.
2 The scientist claim to have discovered cure for AIDS and the medicine will be put on sale very soon.
3 He pretended to have lost her contact number.
4 We hope to have finished the project by the end of march.
5 I'm sorry to have disturbed you.
In all these sentences its use "to have", but purpose is different. For example in 4 it uses for future perspective while in 3 for past. Can someone explain the concept of "to have"? I find it difficult where to use "to have" or not. For example I would write 4th sentence as "We hope to finish the project by the end of march (if I haven't seen this sentence in my book). I also read that we can use perfect infinitive construction to talk about plans which didn't happen. But this rule doesn't follow with 5 sentence.
Thank you

 

[gurpreetgill4u]

I am not a teacher

We do not always use perfect infinitive form for unreal past situations.We can use it show possibility of something.

I wish to have gone to the theater of dreams before I die.

 

[tkacka15]

1 He is understood to have left India for good last year.
2 The scientist claim to have discovered cure for AIDS and the medicine will be put on sale very soon.
3 He pretended to have lost her contact number.
4 We hope to have finished the project by the end of march.
5 I'm sorry to have disturbed you.
In all these sentences its use "to have", but purpose is different. For example in 4 it uses for future perspective while in 3 for past. Can someone explain the concept of "to have"? I find it difficult where to use "to have" or not. For example I would write 4th sentence as "We hope to finish the project by the end of march (if I haven't seen this sentence in my book). I also read that we can use perfect infinitive construction to talk about plans which didn't happen. But this rule doesn't follow with 5 sentence.
Thank you

I understand those sentences this way:

1 He is understood to have left India for good last year. = People understand that he left India for good last year.
2 The scientist claim to have discovered cure for AIDS and the medicine will be put on sale very soon. = The scientist claim that he discovered cure for Aids and the medicine will be put on sale very soon.
3 He pretended to have lost her contact number. = He pretended that he (had) lost her contact number.
4 We hope to have finished the project by the end of march. = We hope that we will have finished the project by the end of March.
5 I'm sorry to have disturbed you. = I'm sorry that I have disturbed you.

 

[engee30]

I also read that we can use perfect infinitive construction to talk about plans which didn't happen.

I'd put it as 'about things that are hypothetical or incorrect', as in:
Sam was getting very anxious about her exam results, because she was hoping to have got/gotten (AmE) them by then. (she still hadn't received them at the time)
I believed the Germans to have won the match. (but, in actual fact, on this rare occasion they didn't)

 

[engee30]

How would you put it then to convey the same meaning?

 

[engee30]

And mine's exactly what you can do to make use of the perfective infinitive out of yours.

 

[engee30]

I do believe that is the case, I'd just hope to find out what other native speakers make of it.

 

[Matthew Wai]

I think it is a comma splice above, but I am not a teacher.

 

[engee30]

Surely it is. I bet Barb_D would pick it up easily.

 

[tedmc]

Is this more natural?

I expected the Germans to have won the match.

 

[Matthew Wai]

I think 'expect' should refer to a future event, but I am not a teacher.

 

[Eckaslike]

I do believe that is the case, I'd just hope to find out what other native speakers make of it.

Hi engee30, I agree with Piscean it doesn't work for me either I'm afraid.

I think it's a common case of what might be theoretically, or grammatically, possible being over-ridden by the native speaker's instinct to chose the shortest way of saying something.

I would naturally use what Piscean wrote:
"I believed that the Germans had won the match".

 

[Eckaslike]

Is this more natural?

I expected the Germans to have won the match.

Hi tedmc. For me, the big problem is the "to have" element. In my opinion, unfortunately, changing any other part of the sentence still won't make it work.

 

[tkacka15]

"I also read that we can use perfect infinitive construction to talk about plans which didn't happen."


Yes, you can use it with modal verbs, for example:

He could have done it as planned.

These elections should have been held as planned.

We use such forms when the planned or expected action was not performed.

 

[Matthew Wai]

I think they are the modal perfect instead of the perfect infinitive, but I am not a teacher.

 

[tkacka15]

I think they are the modal perfect instead of the perfect infinitive, but I am not a teacher.

Everything is possible regarding terminology. I would call such forms as "could + perfect infinitive" and "should + perfect infinitive".