题目

下面有关课本实验，说法正确的是（    ） A．在蛋清溶液中加入适量的蛋白酶，适宜条件下充分反应，再往溶液中加入双缩脲试剂，溶液中不能产生紫色反应 B．用低倍镜可以观察到紫色洋葱鳞片叶外表皮细胞的质壁分离和复原过程 C．用稀释过的红墨水对玉米籽粒进行染色，未煮过的胚不能被染色，胚乳可以被染色，其原因是胚乳细胞的质膜是全透性的 D．探究pH对过氧化氢酶的影响，实验设计中只需采用一份材料连续观察即可8、As Christmas drew near, Ursula was faced with just that problem. She had come to live in an American home and learn English.  21  , she would mind the children and  22  anything she was asked. One of her tasks was to keep track of  23  Christmas presents. Ursula did this faithfully, but she became increasingly 24 . What could she buy for her  25   with the little money she had that would compare with the gifts she was recording daily?  26  ,even without any of the  27  , her employer seems to have everything. Ursula  28  long and hard. On Christmas Eve, she went to a 29 . She moved slowly through crowds of shoppers,  30  things in her mind. Finally she bought a baby dress. She immediately called  31 . “Excuse me, please, can you help me find a poor family with a baby?” “A poor family?” said the 32  driver. “Yes, a very poor family.” Ursula told the man of what she was trying to do. He  33  in silence, and then said, “I know a family who   34   just about everything.” When they reached a   35  , the driver said, “They live on the third floor.” Ursula shook her head, “Would you take this dress to them and tell them it’s from someone ... someone who has everything.” Early the next day, Ursula  36  everyone for the presents she received. Then, she began to     37  why there seemed to be none  38  her. She told about what she did the night before. When she finished, there was a long  39 . “You see,” she added, “I try to do a kindness in your  40   .And this is my Christmas present to you.” 21. A. In return B. As a result C. By the way D. In a sense 22. A. try B. learn C. teach D. do 23. A. delivering B. mailing C. arriving D. sending 24. A. excited B. worried C. tired D. interested 25. A. American family B. own family C. friends D. classmates 26. A. Otherwise B. Therefore C. Besides D. However 27. A. goods B. kindness C. gifts D. help 28. A. talked B. worked C. waited D. thought 29. A. store B. neighborhood C. street D. church 30. A. selecting B. matching C. remembering D. organizing 31. A. a shop B. a taxi C. her employer D. her parents 32. A. delighted B. anxious C. surprised D. respectful 33. A. noticed B. listened C. got out D. carried on 34. A. buys B. has C. uses D. needs 35. A. garage B. building C. station D. yard 36. A. thanked B. encouraged C. praised D. admired 37. A. settle B. repeat C. argue D. explain 38. A. to B. for C. from D. by 39. A. delay B. silence C. time D. break 40. A. case B. opinion C. memory D. name 评卷人 得分 二、选择题 （每空？ 分，共？ 分）