题目

尺规作图“作一个角等于已知角“的依据是三角形全等的判定方法 ． 答案：SSS ． 【考点】作图—基本作图；全等三角形的判定． 【分析】通过对尺规作图过程的探究，找出三条对应相等的线段，判断三角形全等．因此判定三角形全等的依据是边边边公理． 【解答】解：在尺规作图中，作一个角等于已知角是通过构建三边对应相等的全等三角形来证， 因此由作法知其判定依Three men traveling on a train began a conversation about the world’s greatest wonders. “In my opinion,” the first man said, “the Egyptian pyramids are the world’s greatest. Although they were built thousands of years ago, they are still standing. And remember the people who built them had only simple tools. They did not have the kind of machinery that builders and engineers have today.” “I agree that the pyramids in Egypt are wonderful,” the second man said, “ but I do not think they are the greatest wonder. I believe computers are more wonderful than the pyramids. They have taken people to the moon and brought them back safely. In seconds, they carry out mathematical calculations that would take a person a hundred years to do.” He turned to the third man and asked, “What do you think is the greatest wonder in the world?” The third man thought for a long time, and then he said, “ Well, I agree that the pyramids are wonderful, and I agree that computers are wonderful, too. However, in my opinion, the most wonderful thing in the world is this thermos.” And he took a thermos out of his bag and held it up. The other two men were very surprised, “ A thermos?”. They exclaimed. “But that’s a simple thing.” “Oh, no, it’s not, ” the third man “ In the winter you put in a hot drink and it stays hot. In the summer you put in a cold drink and it stays cold. How does the thermos know whether it’s winter or summer?” 1. The three men could not agree on what the world’s greatest wonder was because________.     　 　 A. they could not think of anything very wonderful　　 B. they all had different ideas     　 　 C. they could not prove that their opinions were right   　 D. the journey ended too soon  2. The third man thought a thermos was the most wonderful thing in the world because______.     　 　 A. it lasted longer than the pyramids 　　　 B. it cost less than a computer     　 　 C. he thought it knew whether it was winter or summer　 D. they could do mathematical calculations 3. The third man was not very clever because________.     　 　 A. he could not think of anything to say　　 　　　 B. he did not understand how a thermos works     　 　 C. he did not thinks the pyramids were wonderful 　 D. he did not know anything about computers