Using ing form after "to"

Question

I don't understand why second being is progressive.

He went from being a poor student to being an outstanding one.

Answer 1

I think you may be confusing the preposition "to" used here with the difference between gerunds (verb plus "-ing") and infinitives (to + verb).

sentence with a gerund: I enjoy swimming. (Gerunds do not use "to".)

sentence with an infinitive: I want to swim.

In your sentence, "to being" does not act as a gerund or an infinitive. The preposition "to" connects the first idea (that the student was poor) to the second (that the student became an outstanding one).

Answer 2

Because “it” here in this context doesn’t act like the same you are considering in your mind.

This kind of “to” isn’t infinitive (to + verb1)

Here “it” illustrates moving from place to place (from condition to another) (from being a poor student to being an outstanding one)

This Link explains that there are a few cases where you use to + V + -ing:

1) If the to is part of a phrasal verb or verb + preposition combination: A phrasal verb is something like "look forward to", "confess to", etc. In this case, the "to" is part of the verb itself. Some examples are:

• I am looking forward to attending the party
• I am committed to supporting the Linguistics proposal on Area51

2) If the to is part of an adjective + preposition combination: For example:

• A lot of women aren’t accustomed to being treated so well!
• I am opposed to increasing taxes. These look similar to the examples above, but you can tell that a word like accustomed is an adjective in this case because there is a form of the verb to be. That is, you are an adjective.

3) If the to is part of a noun + preposition combination: For example:

• His addiction to gambling has caused a lot of stress for his family.
• Her great dedication to teaching inspires her students.