Theis is one of the most interesting questions that ____ asked.
| A．have | B．has | C．have been | D．has been |
He is the only one of die students who ____ elected.
| A．are | B．have | C．has | D．is |
The United States of America___one of the most developed countries in the world.
| A．is | B．are | C．was | D．were |
The Olympic Games ____ held every ____ years.
| A．is;four | B．are;four | C．is;five | D．are;five |
A chemical works____ built there.
| A．is to being | B．have been | C．were to | D．has been |