Re: Aspect of the infinitive
   Quote:
  
 
				Originally Posted by JackBoni 
 Я захотел купить книгу
 
    
     Re: Aspect of the infinitive
   Quote:
  
 
				Originally Posted by JackBoni 
 Can someone please explain the use of aspect in the infinitive? If a conjugated verb is in the perfective, can I assume that any infintives relating to it afterwards will be perfective aswell? Does it work the other way also?
 
Я захотел купить книгу
Я забыл сделать работy
 
Спасибо за помощь
 
Джек
 
    Not always.
 
Я захотел спать. 
 
It depends on a specific verb, I think.
 
Я забыл + imperfective = unnatural, should be забыл сделать smth.
Устал + perfective = unnatural, should be устал делать smth.
Я захотел + imperfective = OK (спать, есть, пить...)
Я захотел + perfective = OK (поесть, поспать, попить, купить, сказать) - that depends on a situation:
Я захотел читать = I wanted (suddenly) to read - in a general sense;
Я захотел прочитать книгу - I wanted (suddenly) to have the book read, i.e. to know its contents.
 
I cannot say is there any common rule, that's a difficult question. I'll have to think...