His illness his absence.
| A．explained | B．because of |
| C．accounted for | D．is responsible for |
33. --- How can you be late for such an important conference?
--- Sorry! But my flight was ______ by fog.
| A．taken over | B．held up | C．turned down | D．handed out |
32. The small fishing village has ______ into a modern city in thirty years.
| A．extended | B．existed | C．explored | D．expanded |
31. So serious ________ that even the best doctors failed to save his life.
| A．the man was injured | B．was the man injured |
| C．the man is injured | D．is the man injured |
30. M
r. Keller ______ forty cigarettes a day until he gave it up.
| A．had smoked | B．smokes | C．have smoked | D．smoked |
29. --- Do you know that man?
--- Not really, just a nodding _______.
| A．acquaintance | B．participant | C．relation | D．frequent |