—Oxfam trailwalkers in Hong Kong have to climb________ twenty hills and mountains. —It’s really a tough hike.
— What are the neighbors doing, Joe? — Oh, they _______ a party.
Our English teacher, Mrs. Black, ________ in our school since 1992.
The Olympic Games ________ every four years.
The old people and the children must ____________ in our country.
You ____________ to the ball. Why didn't you go?