go at it

めげずに頑張る

途切れなくやる

喧嘩する

1. A: Is he still practicing for his speech?
  B: Yeah, he's been going at it for three hours now.


2. A: Are they fighting again?
  B: Yeah, recently they go at it almost every night.

3.

He's not the type to give up if he can't do something the first time. He's going to keep going
at it until he gets it.

4.

A: Are you still going at it? It's 2a.m.!
B: I know, but this has to be finished tommorrow.