Clauses of purpose son usados para explicar por qué alguien hace algo. Son introducidos por:
- to-infinitive -> Collin went to the library to borrow a book.
- in order to/so as to + infinitive (Formal) -> The boss requested that everyone work overtime in order to finish the project on time.
- so that + can/will (present/future reference) -> I will give you my number so that you can call me if there are any problems.
- so that + could/would (past reference) -> He left at 5 o'clock, so that he would be at the airport in plenty of time.
- in case + present tense (present or future reference) -> Leave the answer machine on in case anyone calls when we are out.
- in case + past tense (past reference) -> She had made some sandwiches in case we got hungry.
- for + noun (expresa el propósito de la acción) -> We went to Marco's for a pizza.
- for + ing form (expresa el propósito de algo o su función) -> Microwaves are used for heating up food.
- with a view to + ing form -> The Wilson's bought the old farmhouse with a view to renovatong it.
Nota: in case nunca es usado con will o could.
Podemos expresar negative purpose con:
- in order not to/so as not to + infinitive -> I wrote a list of the things I had to do so as not to forget anything.
- prevent + noun/pronoun + (from) + ing form -> The teacher covered up what was written on the board to prevent the students from reading it.
