More bison were killed．The bison population is thought ______ from 60 million to just a few hundred between 1850 and 1910.
| A．to have fallen | B．having fallen |
| C．to fall | D．falling |
In , when he was in , he went to California to seek his fortune.
| A．the 1980s; his twenties | B．the 1980s; the twenties |
| C．the 1980s; twenties | D．1980s; the twenties |
--- Can you tell me how to learn English well?
--- Do more speaking, I think, you’ll be good at spoken English.
| A．or | B．for | C．and | D．until |
from heart trouble for years, my grandma has to take some medicine with her wherever she goes.
| A．Suffered | B．Suffering | C．Having suffered | D．Being suffered |
At first, the company had 15 notebook computers but only one – third used regularly. Now we have over 60 working all day long.
| A．were | B．are | C．was | D．is |
You are not in good health, I think. You could improve your by running every day.
| A．position | B．situation | C．energy | D．condition |