. I ____ to the top of the tree, but I fell off it and hurt my leg.
| A．must have climbed | B．was able to climb |
| C．could have climbed | D．should have climbed |
Finding her car stolen, _______.
| A．a policeman was asked to help |
| B．the area was searching thoroughly |
| C．it was looked for everywhere |
| D．she hurried to a policeman for help |
A cook will be immediately fired if he is found _______ in the kitchen.
| A．smoke | B．smoking |
| C．to smoke | D．smoked |
The boy wanted to ride his bicycle in the street, but his mother told him _______.
| A．not to | B．not to do |
| C．not do it | D．do not do |
We looked everywhere for the keys, but they are nowhere _______.
| A．to find | B．to have found |
| C．to be found | D．being found |
He was reading his book, completely _______ to the world.
| A．lost | B．losing |
| C．to lose | D．to have lost |