What is the logical relationship in English and how to use it?

Logical subject-predicate relationship: it is not a real subject-predicate relationship, but a subject-predicate relationship in the sense.

Non-predicate verbs have their own logical subjects because they are verbs.

The logical subject-predicate of infinitives is generally used as: for sb to do sth(sb is the logical subject, that is, the subject-predicate relationship in the sense of to do)