--- are the Winter Olympic Games held?---Every four years.
Would you mind ______ those old jeans?
I have been skating _______ nine o’clock.
He _____ when the UFO arrived.
The teacher said that they ______ hard-working students.
His father _____ to Nanjing. He _____ back next week.A. has been, is B has been, will be C. has gone, is D. has gone, will be