keep at
phr. v..phr. v.. to continue doing something difficult or boring without stopping.
phr. v.. to persist in a course of action or a specific task despite difficulty, fatigue, or lack of immediate progress.
Learning guitar is hard, but you must keep at it.
If you keep at your studies every night, you will eventually pass the exam.
The researchers decided to keep at the experiment for another year, hoping that a larger data set would finally yield a significant result.
usually followed by 'it' or a noun phrase representing a task or goal.
contrast with 'keep on' (which focuses on repetition of an action) versus 'keep at' (which focuses on persistence with a specific task).
You should keep at to practice.You should keep at it.the phrase requires a noun or pronoun object; it cannot be followed directly by an infinitive verb.