dear sir in theses sentences
1)Any minute, federal agents could come
Blasting through that door.
here i don't understand why they use ing form in blasting
2)I'm afraid I never got further than the first five pages of 'Ulysses'.
here further is adv
3)It was much further to the town centre than I remembered.
here is adj(why)
3)Have you anything further to add?
here it is adj and adv
i don't understand how it can adj and adv in the same time
thank you a lot
1) blasting through that door is a modifying phrase. It tells us how the agents came through the door.
2) I never got further; Here further modifies the verb got.
3) It was much further. Here was is a form of BE, a linking verb. BE verbs take an adjective.