substantiate

"My friend told me there was something in the box, but I didn't know what it was yet. "

"The student substantiated her claim of being sick by showing the doctor's note to her teacher. "

"the old reliables"

"The scientist carefully examined the substance to determine its chemical composition. "

"The experts confirmed it was an authentic signature."

"The historical romance novel was a bestseller in the bookstore. "

"Asphalt, composed of oil and sand, is a widely used material for roads."

"The school required all students to submit their application documents to prove their enrollment. "

"There is no evidence that anyone was here earlier."

"The witness's statement corroborated the victim's account of the incident. "

"He is a student of life."

"to supply money for the war"