plug away

Verb	1.	plug away - work doggedly or persistently; "She keeps plugging away at her dissertation" Synonyms: keep one's nose to the grindstone, keep one's shoulder to the wheel, peg away, slog
	2.	plug away - persist in working hard; "Students must plug away at this problem" Synonyms: plug

keep one's nose to the grindstone, keep one's shoulder to the wheel, peg away, slog, work