— What do you think of the White House?
— Splendid. While I was studying in America, I it twice.
| A．have visited | B．had visited |
| C．visited | D．would visit |
In that traffic accident last night the man who hit five people in a row had drunk so much that he could no longer_______ between fantasy and reality.
| A．distinguish | B．disguise | C．disturb | D．disgust |
Mr. Andrew taught his students how to develop the basic skills in the physics class, ______ everything through jokes and experiments.
| A．to explain | B．explained | C．explaining | D．explains |
Mr. Bryan is a/an _______ secretary in our office, for he is able to do tasks successfully, without wasting time or energy.
| A．effective | B．efficient | C．flexible | D．sufficient |
There was enough evidence to prove that the explosion in Robinson’s house _______ the leak of natural gas.
| A．resulted in | B．resulted from | C．led to | D．contributed to |
The Browns have six children altogether. It is obvious that ________ little money the present job brings Mr. Brown can hardly support so large ________family like that.
| A．/; the | B．a; the | C．a; / | D．the; a |