1. Can I put the word "to" in the spot indicated? I think a lack of a ??? context might pose a difficulty but please try it.
Helping an children (to????) learn
2. I have difficulty in knowing how to use this words "have got" in sentences? What are they?
My students have already got all part-time jobs.
3. Why doesn't the phrase "change of state" have an article in front of its word "state" when the word is known to be a countable noun?
that suggests transience or change of state.