Are you good at playing _______ guitar or _______ basketball?
—Don’t worry. Your uncle is coming to help you. —________he doesn’t come?
My friend’s flight had taken off _________ I got to the airport to see him off.
The monkey was seen _________off the tall tree.
—What do you think about the idea? —I am really against _________ a running race in the street.
—Do you know whose dictionary it is? —It ________ be Ann’s. Look! Her name is on the first page.