conjectural

"I explained it, but it is pure conjecture whether he understood, or not."

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

"The effectiveness of that new medicine is still unproven, so doctors are hesitant to prescribe it widely. "

"The theory of gravity explains why objects fall to the ground. "

"The company dismissed me after less than a year."

"The teacher limited the time students had to complete the assignment to one hour. "

"Without knowing the exact amount of money needed for the trip, all we could do was guesswork. "

"The historian wrote a book about her family's history. "

"The ancient pottery shards are considered artifacts of the lost civilization. "

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

"The detective investigated the theft of the school's valuable computer equipment. "

"The conclusion of the meeting was that everyone would work on the project together. "