I need to make an analysis of this sentence:
....and we can use them to help you to buy the best product.
or
....and we can use them to help you buy the best product.
We - subject,
can use - verbs, them - indirect subject, to help you buy the best product - direct subject.
Am I right?
I'm not sure if to use to buy or just buy and if it is the part of subject or another sentence.
....and we [can [use them [to help you [buy the best product]]]].
No, you've got the analysis mostly wrong.
This is a complex catenative construction with a number of catenative verbs, two intervening nouns as objects, and two catenative complement clauses.
"Can" is a catenative verb and the non-finite clause "use them to help you buy the best product" is its catenative complement.
"Use" is a catenative verb, "them" is its direct object, and the non-finite clause "to help you buy the best product" is a catenative complement of "use".
Likewise, "help" is a catenative verb with "you" as its direct object and the non-finite clause "buy the best product" is catenative complement of "help". Finally, "the best product" is direct object of "buy".
I've bracketed the catenative complement clauses.
Them is the direct object of the verb 'use'. To help you (to) buy the best product is a non-finite clause functioning as a 'catenative complement'. This catenative complement is licensed (allowed) by the catenative verb 'use'.
Direct objects normally answer the question 'what'.* But To help you (to) buy the best product clearly does not answer the question of 'what do we use?'
It's called 'catenative' because of it's ability to form chains in a catenative construction. †
