'does diligent' is not correct or usable in written English.
To make the sentence correct, you will need to replace 'does' with 'is' or another verb, such as 'do' or 'works'. For example, 'He is diligent in his work.'.
I've no wish to pick on my old sparring partners at Media Lens – run by David Edwards and David Cromwell, who do diligent and thoughtful work.
Summer recruitment: "They look to have continued their ability to do diligent business abroad.
Since 2013, Bay Area native Jim Hopkins has been doing diligent work to preserve the archives of San Francisco's disco history with his non-profit SF Disco Preservation Society.
These comparisons aren't new, either, but Mr. Stone does a diligent, sometimes eerie job of articulating them.
If only all our pension fund managers did such diligent research before investing.
But most are doing their diligent best with the rice grain and lentil bookkeeping.
3.36pm GMT 103 min: After that initial wobble, Gascoigne has managed to refocus and is doing some diligent defensive work.
Should the IEC and the ECC watchdogs do a diligent job of exposing fraud and come to disqualify huge numbers of votes in the process then the international community may have to revise its enthusiasm.(Picture credit: AFP).
She has done a diligent job of building a bipartisan coalition pressing for more sweeping change, and further debate about the sexual assault problem and its solutions can help strengthen the result when the Senate negotiates a final bill with the House.
The hijackers reportedly spent the day before at local strip clubs in Miami, and so, in doing his diligent research for the book, Mr. Dubus rented a convertible, enlisted his brother and best friend from high school -- large men whom nobody messes with -- and had an awkward conversation with his wife: "Honey, I need to go to Florida and I need to see some strip clubs".
