I would like to know the differences between "to" and "for" with infinitives and gerunds, related to purposes and uses, i.e.:
I need that machine TO SEND mails. / This machine is FOR SENDING mails.
Every night I enjoy TO WATCH TV. / TV is FOR WATCHING TV.
I'm confused!! I can use it without difficulties but I need to prepare a lesson with that grammar point but I do not know how to explain it! The lesson is about the use of "to" and "for" in purposes and uses, to avoid confusion.
I am not a professional teacher. My claifications for richimoon are as follows: "While going through page referred to by anglika you might have come across an important comment about the use of ‘To’ with a verb (infinitive form)to act as a noun, adjective or adverb and also as a preposition when it takes a noun or pronoun as its object. Examples: He used a computer to send e-mails to his friends. Here “to send” acts as an adverb to the verb used and “his friends’ as object of the preposition ‘To’. Taking your example: Computers are used TO SEND e-mails. Here “To send” acts as a noun and direct object of the verb “used”
Added to the confusion, you have used another preposition ‘for’ which usually takes a gerund as its object. I take your examples which have created doubts in your mind. Examples: I have a computer FOR SENDING e-mails. Computers are used FOR SENDING e-mails. Here the ‘ing’ form verb send i.e. sending is a gerund and acts as a object of thev preposition ‘for’. So both the sentences are correct."