题目

为研究锌和铝的金属活动性，某研究小组进行了如下探究。  （1）小明设计的实验方案：向表面积相同的铝片和锌粒中分别加入盐酸。写出铝与盐酸反应的化学方程式：                                               。（2）小芳将去膜和未去膜的铝片分别放入盐酸中，发现前者比后者反应快，原因是未去膜的铝片表面有            （填化学式）， （3）小芳在（2）实验中，还观察到有“灰黑色沉淀”这一异常现象出现。 阅读理解(每小题2分，共30分)A易读度★★☆    I work as a dentist’s assistant(助理) and people often have “good” reasons why they can't come to see the dentist. When I hear them,I can't help laughing.    Roland liad an 11 0’ clock appointment(预约) .He phoned at 12 0’ clock and said, “I'm sorry that I missed my appointment. My dock broke."    And then there was Sally who said,“I’m sorry I couldn’t come yesterday for my appointment but my pet mouse died.”    Colin,who always finds a good excuse (理由) notf to come for his appointment,rang and told me, “My sister called the police and said I had hit her. They asked me questions for three hours before they decided it was a joke!”    One of the best excuses came from 12-year-old Tim who came about two hours late for his appointment. He said that an elephant had sat on a car in front of his bus!And this caused such a traffic yam (交通堵塞) that no cars could move for an hour.    13-year-old Rachel Stuart rang yesterday. This is how that talk went:    “Hello,Doctor Bowden's office. How can I help you?”    “This is Mrs. Stuart. I'm afraid my daughter Rachel cannot come for her appointment this morning. She has to stay at home because she lost her voice (失声)    “I see. And who am I speaking to,again?”    “My mother."根据材料内容选择最佳答案。() 46. What was Roland's excuse for missing his appointment?    A He got up very late.   B. His pet mouse got badly    C. He had a big fight with his sister.   D. There was something wrong with his clock.() 47. The underlined word “They” in Paragraph 4 refers to “”.   A. Colin's parents,      B. The police    C. Colin's sisters      D. The doctors() 48. From the passage,we can know that Tim.   A. lost his voice in an accident   B. went to see his dentist by bus   C. saw an elephant in front of a car'   D. was one hour late for his appointment() 49. Who called to say that Rachel couldn,t come for her appointment?   A. Rachel herself.     B. Rachel’s mother,   C. Rachel's friend.   D. Rachel's grandmother.() 50. In the writer,s opinion,the excuses are all.A. popular   B. funny C. creative   D. strange