The poet，obviously not __12__ the answer，didn’t stop to think about the scientist’s question.He took a $5 bill __13__ his pocket and handed it to the scientist.
The scientist __14__ accepted the bill and at once said, “Okay，now it’s your turn.”
The poet thought about this for a few minutes，then asked, “All right，what goes up a mountain on three legs，__15__ comes down on four？”
The bright glow quickly disappeared from the scientist’s face.He thought about this for a long time __16__ his notebook and making numerous calculations (计算)．He finally __17__ and took out his laptop (笔记本电脑)，using his Multimedia (多媒体的) Encyclopedia (百科全书)．As the plane was __18__ the scientist gave up.He handed the poet a __19__ bill.
The poet accepted it happily，getting ready to stand up，“Wait！” the scientist shouted, “you can’t do this to me！What’s the answer？”
The poet looked at the scientist and calmly put a __20__ bill into his hand.
1．A.boat B．plane
C．car D．bus
2．A.play B．read
C．invent D．find
3．A.show B．introduce
C．give D．ask
