题目

小明探究“电流跟电阻的关系”的实验电路如图所示。 （1） 图中的a是表，b是表。 （2） 连接电路后，闭合开关，两表均有示数，但无论怎样调节滑动变阻器的滑片，两电表示数均保持不变，其原因可能是（写出一个即可）。 （3） 排除故障后继续实验。闭合开关，移动滑动变阻器滑片，当5Ω的电阻两端电压为1.5V时，电流表的示数（如图所示）为A。 （4） 再分别换接10Ω、15Ω的电阻，重复上述实验，得到表中的实验数据，分It was Sunday morning. A butcher(屠夫) heard the doorbell(门铃) and thought it must be a customer. But he was surprised to see that a dog was coming into his shop. The dog had $10 and a note in its mouth. The butcher took the note and read it. It said,“10 pork chops(排骨), please.”So the butcher took the money and put a bag of chops in the dog’s mouth.Then he quickly closed the shop because he decided to follow the dog. He found the dog on the street. The dog was waiting for a green light. Then the dog walked across the road. The dog went to a bus stop. When a bus arrived, the dog checked the number and then got on the bus.After a while, the dog stood up on his back paws(爪子) to push the “stop” button(按钮). The bus stopped and the dog got off. Then the butcher followed it to get off the bus.The dog ran to a house and dropped the bag in front of the front door. It then began to beat its head against the front door. After a while, a big man opened the door and began shouting at the dog. The butcher ran up and shouted at the man, “What are you doing? Your dog is a genius(天才).”The owner of the dog said, “Genius? No way! I always tell him to take the keys when he goes to the stores. But he never listens to me!”56. Who was the customer that Sunday morning?A. A big man.　　　　　　　　　　　　　　　　　　　　　　　 B. A butcher.　　　　　　　 C. A dog.　　　　　　　　　　　　 D. A little boy.57. How much did the dog pay for the pork chops?A. $20.　　　　　　　　 B. $10.　　　　　　　 C. $5.　　　　　　　　　　　　　　　　　　　　　 D. $62.58. How did the dog take the note?A. In the bag.　　　　　　 B. On its back.　　 　C. In its mouth.　　　　　 D. Around its neck.　 59. Which is NOT right according to the story?A. The dog stood up on its back paws to push the “stop” button.B. The butcher quickly closed the shop to follow the dog.C. The big man was pleased with his dog.D. The butcher thought the dog was a genius.60. What is the story mainly about?A. A customer. 　 B. A smart dog.　　　　　 C. A butcher.　　　　　　　　　　 D. A big man.