Infinitive of purpose

Do we use the infinitive of purpose to express a person’s objectives?

Does it tell the other person the reason why something is being done?

Does It inform about the reason of doing something?

Do we need to have a normal verb as well?

Can we use these structures that are similar in meaning to express this situation?

in order to

so as to

to

Do we use in order to to be more formal?

Do we use so as to for everyday use?

Do we use to as a short form of these two forms above?

I went on holiday (this is what I did) to relax (this is why I did it).

She studies hard (this is what I did) to pass her exams (this is why I did it)..

He stopped smoking (this is what I did)  to become healthy (this is why I did it)..

I went to the bank to ask for a loan.

Be careful! Do they use ‘for + infinitive’ in many languages?

Is this correct or incorrect in English?

I went to my room for relax. incorrect

I went to my room to relax. correct

I go to work for make money. incorrect

I go to work to make money. correct

I am here for study English. incorrect

I am here to study English? correct

Do some students use for to together as a mistake?

I went to the cinema for to watch a movie. Incorrect

I went to the cinema to watch a movie.

Can the main verb be in any tense?

Present simple: I go to the cinema to watch a movie.

Present continuous: I am going to the cinema to watch a movie.

Past simple: I went to the cinema to watch a movie.

Past continuous: I was going to the cinema to watch a movie.

Future simple: I will go to the cinema to watch a movie.

Present perfect: I have gone to the cinema to watch a movie.

Can we also use ‘in order to + infinitive’ and ‘so as to + infinitive’?

Is ‘In order to’ a bit more formal but the meaning is the same as ‘so as to’ and ‘to + infinitive’?

I went to the cinema to watch a movie.

I went to the cinema in order to watch a movie.

I went to the cinema so as to watch a movie.

Can we use a negative infinitive of purpose by adding ‘not’ before ‘to’?

Do we often do this with ‘in order not to’ and ‘so as not to’?

I did things carefully in order not to make a mistake.

I did things carefully so as not to make a mistake.

Can we only use the infinitive of purpose if the subject of the main verb and the infinitive of purpose are the same? 

Do we use ‘so that + clause’ or ‘in order that + clause” if they are different?

I went to the park to play football. (I went to the park and I played – the subject are both ‘I’= the same)

Vs.

I went to the park so that my children could play. (I went to the park, but my children played. The two subjects are different – I and John – so we can’t use an infinitive of purpose.)

I am here so that you can learn these concepts.

Parents suffer so that their kids can live comfortably.

With the verbs ‘come’ and ‘go’, do we use an infinitive of purpose when they’re in a normal tense but we often use ‘and + infinitive’ with imperatives or after modal verbs?

I went to my room to study.

Vs.

Go to your room and study!

You must go to your room and study!

Do we use “for + noun”?

I am here (action) for an English class (reason why).

My friend came to my house (action) for a coffee (reason why).

We went out (action) for a meal (reason why).

Are you here for an English class or a French class?

How often do your friends come to your house for a coffee?

When was the last time you went out for a meal?

Can we also use “for + ing” if the subject is an object?

A pen is used for writing with. A pen is used to write with.

This room is used for working in. This room is used to work in.

A house is meant for living in.  A house is meant to live in.

Can we use both of these structures?

What is used for writing?

Which room in your house is used for cooking?

What kinds of areas/places are not good for living in?