--- Did your father come back early last night?--- Yes. It was not yet eight o’clock _______ he arrived home.
Is this museum ___ some foreign friends visited that day?
Edison never stopped ___ new and better ways to do things.
Although it’s raining, ___ are still working in the fields.
Is ___ possible to fly to the moon in a spaceship?
Of all the boys, Tom spent __ time and made ___ mistakes.