Unless ________ , the murderer is likely to commit similar or further offences.
| A．to arrest | B．arrested | C．been arrested | D．arresting |
108. Dr. Manette had been mentally ____ by his long years alone in prison and his hair had turned white.
| A．disturbed | B．troubled | C．worried | D．Damaged |
107. The Curies are best known for ____ radium and they won the Nobel Prize in 1903.
| A．discovering | B．inventing | C．finding | D．Creating |
106. Where are my keys? They seem to have ____.
| A．found | B．appeared | C．disappeared | D．Discovered |
105. The waters of this great lake, which is also the world's deepest, have been ____ by waste from a chemical factory.
| A．cleaned | B．cleared | C．dirtied | D．Thrown |
104. --- What do you do in the theatre?
--- I ____ plays.
| A．act | B．direct | C．perform | D．Watch |