AIDS is said ______ the biggest health challenge to both men and women in that area over the past few years.
He has never visited the Great Hall of the people, _________?
A number of sheep _________ seen by us when we passed the field..
Both Kate and I _________ ready for the picnic now.
A boy with two dogs _______ when the earthquake rocked the city.
Andy has _______ for five years. Five years _________ a long time.