In a diligent manner, with appropriate effort, carefully.(adverb)
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Use "diligently" in a sentence
"In one case a woman came in diligently every week for a year."
"I wish I were there to personally thank her and through her, her husband Bill for the good works they are doing for mankind and, for her being so sincere and honest in diligently serving President Obama after the bitter rivalry they went through during the primaries."
"Though Mr. Fowler was not an ordained preacher and did not possess an advanced degree in theology, he studied diligently from the Greek New Testament for more than 30 years."