validating

"Check the oil in your car once a month."

"I parked the drive heads of my hard disk before travelling with my laptop."

"He is a student of life."

"He successfully climbed the mountain."

"My daughter's teacher is very kind and helpful. "

"The army cashiered the soldier for insubordination. "

"The validity of the student's excuse for missing class was questioned by the teacher. "

"He is a student of life."

"The expiration of the library book's due date meant I had to return it. "

"The teacher validated the student's parking pass after checking their ID. "

"The teacher patiently explained the math problem, and the students were able to understand the steps involved. "

"The explanation was long and drawn-out."