I think the grammar of To-infinitive is the most difficult part of learning English because it is hard for me like ESL students to know which is which. I mean, I'm, well, just wanting to classify the grammar of to-infinitive...
I learned that to infinitive phrase can be used to show the purpose or intention of subject, purpose clause.
I used a knife to cut the bread.
I submitted the recipe to win the prize money.
And I learned that to infinitive phrase can also be used as a relative clause.
There were a lot of people here to see the movie.
He is the man to wash the dishes.
And I'm lost. If it is used with two ways, I don't know what reading is preferential in some sentences.
Here are some sentences which I'm confused about.
a.We asked for a man to talk to the children
b.You need a key to unlock the door.
c.Now you can use a key to get into Google account
Are the objects in the sentences antecedents to infinitival relatives?
Or rather, are the to-infinitival clauses just purpose clauses?
As for my interpretations, Here they are.
a1. We asked for a man who was to talk to the children. [relative reading]
a2. We asked for a man (for him) to talk to the children. [purpose reading]
b1. You need a key which is to unlock the door.
b2. You need a key in order to unlock the door.
c1. Now You can use a key which is to get into Google account.
c2. Now You can use a key for Google account.
Which interpretations are closest in meaning to the original sentences?
I'm hoping my words get across to you.