syntactic function of the infinitive

[Kacenkaa]

Hi,
Please, ​would anyone know what function the infinitive structure has in this sentence:

They were known to be alone together.

I wonder whether it is tough movement or subject raising, or something totally different?
Thank you very much for any help!!

 

[BobK]

Sorry I don't know those words, and anything I say will be off the point - which doesn't normally prevent me from sticking my oar in (but this time it has done ).

b

 

[Rover_KE]

Hi,
Please, ​would anyone know what function the infinitive structure has in this sentence:

They were known to be alone together.

I wonder whether it is tough movement or subject raising, or something totally different.

I guess it's something totally different, but I've no idea what.

Rover

 

[emsr2d2]

If you can explain to us what on earth "tough movement" or "subject raising" are in relation to English grammar, we might stand a chance of answering your question.

 

[Kacenkaa]

Hi,yes..Tough movement is for example in sentence Jane is a pleasure to teach, where the syntactic subject of the sentence is Jane, but Jane is asctually the object of teach (to teach Jane). Subject raising is for example in Jane seems to win, where Jane is syntactically the subject of seems, but it is actually the semantic subject of to win..thus the subject is raised. But I think is neither of them. Can someone please try to guess the syntactic function of the infinitive in the They were known to be alone together.?
Thank you very much, I appreciate any help.

 

[emsr2d2]

The Wikipedia article on "tough movement" suggests that it refers to sentences such as "This project is hard to complete" (rather than "It is hard to complete this project") and that it usually refers to sentences with "hard/easy/tough/simple etc" in. The example sentences all seem to begin with a noun or proper name. I would say the pattern I have seen does not fit your example sentence. I reiterate that I had never come across this term of syntax​ before.

 

[Kacenkaa]

Yes, it's true, but what do you suggest as a syntactic function of the "to be" in the sentene above then? I am really clueless...