—_______ is your grandpa? — He is seventy-five.
He found_ ________very difficult ________the math problem.
— What did Tina say? — Sorry, I didn’t ________ what she said.
—Do you know _____ ? I'm going to see him. —Sorry, I don't know.
I often make mistakes ___________ grammar..
--- ________. Could you tell me the way to the station?