A world-famous scientist, Dr．Halogen, was on his way ___________（give） another lecture．This night, his driver_____________（ask） him for a favor．“ Dr．Halogen, when you speak, everyone gives you honor and attention．I’d really like to see what that __________（feel） like．Could we exchange clothes just for tonight? You’ll be the driver and I _______（be） the scientist．”
Dr．Halogen laughed and said, “Do you really think you can do it? What if someone__________（ask） you a difficult question?”
“I can answer it,” said the driver．“I ____________（hear） you speak on this topic many, many times．”
“All right,” said the scientist．“It’s April Fool’s Day after all!”
The two men exchanged clothes and continued on to the meeting．When they arrived, the bogus（假冒的） scientist________________（receive） warmly．He gave a good speech and answered a few questions．Then a man asked a very tricky one．After______________（think） quickly, he said, “Oh! That question has a very simple answer．It’s so easy．I ____________（let） my driver, who___________（sit） in the back row, explain it!”