________ caused the accident is still a complete mystery.
—Where is your sister?—She’s gone away __________ the weekend.
She doesn’t know anyone here.She has got __________ to talk to.
He __________ his sight ten years ago.Since then he has been blind.
They have held three meetings this week _________.
The faces of four famous American presidents on Mount Rushmore can be seen from a _________ of 60 miles.