"keep diligent" is a correct phrase and can be used in written English.
It means to continue being hardworking, careful, and thorough. Example: "In order to succeed in your studies, it is important to keep diligent and maintain a consistent study schedule."
Many others throughout the history of this country have kept diligent records — their own realometers — of flowering, bird migrations, butterfly emergence, fish runs and the like.
He keeps diligent notes in a small, spiral-bound notebook while out on the street, and later enters them into a comprehensive database the program keeps on every homeless person it encounters.
With the funding and manpower necessary to keep a diligent watch, the army developed their own policies and regulations that permitted public access while protecting park wildlife and natural resources.
keep a diligent eye on your surroundings.
School bullies, mean teachers and even abuse are things we as parents have to be aware of and keep a diligent eye on.
TechCrunch is lucky enough to have a really smart, well-informed readership which keeps us diligent in our reporting.
In virtue of his sampling plan, the other samples with five failures, namely the ones which kept the diligent researcher from including the observed sample in the region of rejection on pain of exceeding the error probability, could not have been observed.
But in an e-mail message he wrote: "I don't think for one second that this was a glitch," adding, "We have to now keep a more diligent eye on Amazon and how they handle the world's cultural heritage".
Larry Kramer told the New York Times that he didn't believe "for one second that this was a glitch" and that "we have to now keep a more diligent eye on Amazon and how they handle the world's cultural heritage".
The Editorial team will be diligent to keep the review process short.
