The United States of America _____one of the most developed countries in the world.
| A．is | B．are | C．was | D．were |
I _____ in the street when someone _____ me.
| A．walk; called | B．walking; calling |
| C．was walking; called | D．walked; called |
The number of people who _______ invited to the meeting _____ fifty, but a number of them _____ absent for different reasons.
| A．were; was, was | B．was; was, were |
| C．were, was; were | D．were; were, was |
The early pioneers had to _____ many difficulties to settle down on the new land.
| A．get along with | B．go after |
| C．go over | D．go through |
The teacher called Tim’s mother ________ what he had done in the test.
| A．because of | B．because |
| C．since | D．as |
--You are always full of ________. Can you tell me the secret?
--Taking plenty of exercise every day.
| A．power | B．energy |
| C．force | D．strength |