题目

下列物质的用途中，利用其化学性质的是（ ） ①氦气用于冲灌空气球；②氧气用于电焊；③干冰用于制冷；④用自来水制造蒸馏水． A．①、②、③   B．②   C．①、④   D．①、④、⑤ 答案：【考点】化学性质与物理性质的差别及应用．  【专题】物质的变化与性质． 【分析】物质的化学性质是指在化学变化中表现出来的性质，物质的物理性质是指不需要通过化学变化表现出来的性质，据此进行分析判断． 【解答】解：①氦气用于冲灌空气球，是利用了氦气的密度小，不需要发生化学变19、One weekend, all of the hotels in Green City were full because there was a large meeting. Mr. Black was the manager of a   1   in the city. On Friday night, three men came into the hotel and asked for   2   . Mr. Black said there were   3   rooms ready because of the meeting. The men were unhappy. Mr. Black wanted to help them. He remembered that Room 418, a small room, was   4  . He asked them if they would share a room. The three men said they would. Mr. Black said the room would be thirty dollars,   5   for each one. Each man gave him the money and then went up to the room. Mr. Black soon began to feel sorry, so he called his assistant over, gave him five dollars and said, “  6   the money to those three men in Room 418. I asked too much for their room.” The assistant took the money. While he was   7   the way there, he started to think, “How can three men divide five dollars? I will give them each one dollar and keep two dollars for   8   . The men will be   9   to get something back. And Mr. Black will never know.” So the assistant returned one dollar to each man. The next morning, the three men went to thank manager before they left. They said, “Thank you for   10   us three dollars back.” Mr. Black was surprised but he said nothing. After the three men left, Mr. Black called the assistant to his office and said, “I’m sorry, but I don’t think you can stay here any more.” 1. A. library                          B. shop                  C. factory            D. hotel 2. A. drink                            B. rooms                C. money            D. food 3. A. no                               B. some                 C. many              D. several 4. A. dirty                            B. empty                C. dark                D. full 5. A. thirty                           B. three                  C. ten                  D. two 6. A. Bring                           B. Carry                 C. Take               D. Lend 7. A. on                               B. by                     C. in                   D. off 8. A. themselves                   B. himself              C. yourself          D. myself 9. A. happy                          B. angry                 C. sorry              D. worried 10. A. lending                       B. giving                C. returning         D. taking 评卷人 得分 六、阅读理解 （每空？ 分，共？ 分）