The two friends _____ on the Internet for three hours, and they would go on till the next morning.
"All____ present and all____ going on well," our monitor said.
Many a man ____ come to help us.
Theis is one of the most interesting questions that ____ asked.
He is the only one of die students who ____ elected.
The United States of America___one of the most developed countries in the world.