authoritative

"He is a student of life."

"The headmaster announced the school's new sports program. "

"The teacher convinced the students that the Earth revolves around the sun, using diagrams and explanations. "

"The rumor is originating from a misunderstanding in the office. "

"accurate knowledge"

"The king commanded his servant to bring him dinner."

"Professor Smith, the head of the history department, gave a fascinating lecture on the Roman Empire. "

"Listen carefully when someone instructs you how to assemble the furniture."

"The teacher used the definitive "the" in the sentence to specify the particular book assigned for homework. "

"Professor Lee's lecture was very scholarly, filled with detailed research and thoughtful analysis. "

"He still has nightmares resulting from the treatment he received from his captors."

"I have the authority to penalise the staff in my department, but not the authority to sack them."