题目

用下列实验操作可完成两个实验。甲实验为粗盐中难溶性杂质的去除，乙实验为配制溶质的质量分数为10%的氯化钠溶液。下列说法中，正确的是（    ） A.甲实验的步骤是①④⑤，其中去除杂质的关键步骤是蒸发 B.甲实验各步操作中，玻璃棒的作用都是相同的 C.乙实验若按照②③①的步骤进行操作, 则配制的溶液浓度偏大（ρ水=1 g/cm3） D.乙实验中，若①所用的烧杯内壁沾有水，对配制的溶液浓度无影响25、One evening Mr. Harris was on duty when the phone rang. He went to answer it. It was Mrs. Green.       "Please, sir, come to my house. I had 5,000 dollars stolen. "       Mr. Harris hurried to her house. He asked Mrs. Green, "When did you find the money missing?"       "At seven, I put my money on the table in the living - room. Then I went to wash my hair. I came back at seven thirty and the money was gone. "       "I see," Mr. Harris said, "Were you alone in the house?"      "No. My sister's daughter, Nancy, was here, too."       "Let's talk to Nancy," said Mr. Harris. They went to Nancy's room.       Mr. Harris sat on the only chair in the room. The chair was cold. Mrs. Green and Nancy sat on the bed. Mr. Harris saw some books on the floor near the chair.       "What have you been doing this evening?"       "I've been studying because. I shall have a test tomorrow. I've been sitting on that chair reading all the time. I never got up and never left my room. But at about seven fifty I heard a sound, like someone closing the door. I didn't go out to have a look, for I was too busy. Maybe someone came into the house and took my aunt’s money. "       After heating that, Mr. Harris was quite clear. He said to Mrs. Green, "Well, you won't have to be worried, and you’ll find the 5,000 dollars just in this room. " 46. In which order did the following happen? a. Nancy went back into her room.    b. The money was stolen.     c. Mrs. Green washed her hair. d. Mrs. Green put the money on the table.    e. Mrs. Green gave Mr. Harris a phone call.    f. Mrs. Green returned to the living- room.    A. e. d. c. b. a, f.                 B. d. b. c. a. f. e C. d. c, b, a. f. e.                 D. a. b. c. d. f. e. 47. The chair was cold. This suggested (暗示) that      A. there was another chair in Nancy’s room    B. Nancy did not tell the tree facts C. Nancy forgot to close the windows in her room      D. it was cold that evening 48. Mr. Harris paid attention to all the facts except the fact that       A. Nancy and her aunt sat on the bed     B. some books were on the floor C. there was only one chair in the room    D. the chair was cold 49. Which of the following is the most probably true?    A. Mr. Harris was a policeman. B. Mrs. Green found Nancy stole the money between 7 and 7: 30. C. The money was hidden in Nancy's bed. D. What Nancy said sounded reasonable. 50. Which of the following do you believe?     A. The thief broke into the house, stole the money and left the house with the money. B. Nancy was preparing for the test.     C. Someone closed the door at 7: 50.     D. Nancy stole the money. 评卷人 得分 七、阅读填空 （每空？ 分，共？ 分）