How are “working”, “work” and “to work” in these sentences different?

English as a Second Language English Vocabulary, Grammar and Idioms
1

Greetings:

Could some nice person explain to me how these sentences are different (if they are in fact different):

  1. She started working here last year.

  2. She started work here last year.

  3. She started to work here last year.

Frankly, I also don’t understand the grammar. I know the main verb in each sentence is in the past, i.e., “started”, but after that I am confused. How is “working” in sentence #1 different from “work” in sentence #2 grammatically? How is “work” in sentence #2 different from “to work” in sentence #3 and so forth? Any information given is greatly appreciated.

2
  1. She started working here last year. (Gerund)
  2. She started (her) work here last year. (Noun)
  3. She started to work here last year. (Infinitive)

All these sentences mean almost the same.