摘要: (1) down adv. 向下, 如:Sit down, please. (2) down prep. 沿着, 如:The post office is down Bridge Street on the right.

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(10分)植物具有向重力生长的特性,下列是研究根向重力生长机理的两个实验。
实验一:将空白琼脂和含EDTA的琼脂做成帽状,分别套在甲、乙两组玉米胚根的根冠外(示意图如下)。提示:EDTA的作用是去除与其临接部位的 Ca2+。

将胚根水平放置培养一定时间后,观察到甲组胚根向重力(下)生长,乙组胚根水平生长。根据上述实验结果,得出实验结论:                               。
  实验二:水平放置的胚根弯曲向下生长,与根冠近地侧的Ca2+浓度明显高于远地侧有关。研究表明,根总是朝着Ca 2+浓度高的方向弯曲生长。为验证这一结论,有人设计了下列实验方案。请根据提供的实验材料和用具,写出第二步及以后的实验步骤和实验结果,并回答问题。
(1)实验材料和用具:胚根等长的萌发玉米种子,空白琼脂帽,含EDTA的琼脂帽,上面部分含Ca2+的琼脂帽(水平方向),培养皿等。
(2)实验步骤:
  第一步:取若干个培养皿,在每个培养皿中放置适量的萌发玉米种子,按实验一中乙组的方法处理胚根一定时间后,移去根冠外的琼脂帽。然后将培养皿平均分成两组,编号为 A组、B 组。 
  第二步:                                                            。
  第三步:                                                            。
(3)实验结果:                                                         。
(4)科学家进一步证实,根冠中生长素的分布受Ca2+浓度影响,当胚根水平放置时,重力诱导Ca2+向根冠下侧移动,导致近地侧的生长素浓度比远地侧高。请分析胚根的生长素分布与向重力生长的关系:                                  。
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A man got a new car and he was very proud  26  it. One day, when he  27  back home, he saw his three-year-old son  28  hitting the new car with a toy hammer. The man was  29  angry that he ran to his son, grabbed the hammer from  30 , and used the hammer to hit the little boy’s hands too hard. The  31  boy cried out but his father didn’t care.
When the father  32 , he took his son to the  33  as fast as he could. Although the doctor tried his best to save the  34  bones(骨头), he had to cut the fingers from both of the boy’s hands in the end.
When the boy  35  in the hospital and saw his hands, he innocently(天真) said, “Dady, I’m sorry about your car.” Then he asked, “but  36  are my fingers going to grow back?” The father  37  very sad.
Think about the story when  38  steps on your feet or when you wish to take revenge(报复). Think first before you lose your patience with someone. Cars can  39 , but broken bones and hurt feelings often can’t.
  People often make mistakes. But we should remember that forgiveness is greater than revenge.  40  before act!

【小题1】
A.to    B.ofC.inD.from
【小题2】
A.comesB.came   C.has come D.is
【小题3】
A.happy  B.unhappy  C.happilyD.luckily
【小题4】
A.too   B.veryC.so    D.such
【小题5】
A.it    B.her    C.heD.him
【小题6】
A.poor   B.lucky   C.bad    D.small
【小题7】
A.came out B.came down C.calmed downD.calmed out
【小题8】
A.school  B.hospitalC.shopD.home
【小题9】
A.breakB.breaking  C.brokenD.broke
【小题10】
A.stood upB.got upC.woke up  D.put up
【小题11】
A.how   B.whereC.why   D.when
【小题12】
A.feltB.fellC.sounded  D.looks
【小题13】
A.anyoneB.everyoneC.no oneD.someone
【小题14】
A.repairB.repairedC.be repairedD.be repairing
【小题15】
A.To thinkB.ThinkingC.Think   D.Be thought

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A man got a new car and he was very proud  26  it. One day, when he  27  back home, he saw his three-year-old son  28  hitting the new car with a toy hammer. The man was  29  angry that he ran to his son, grabbed the hammer from  30 , and used the hammer to hit the little boy’s hands too hard. The  31  boy cried out but his father didn’t care.
  When the father  32 , he took his son to the  33  as fast as he could. Although the doctor tried his best to save the  34  bones(骨头), he had to cut the fingers from both of the boy’s hands in the end.
  When the boy  35  in the hospital and saw his hands, he innocently(天真) said, “Dady, I’m sorry about your car.” Then he asked, “but  36  are my fingers going to grow back?” The father  37  very sad.
  Think about the story when  38  steps on your feet or when you wish to take revenge(报复). Think first before you lose your patience with someone. Cars can  39 , but broken bones and hurt feelings often can’t.
  People often make mistakes. But we should remember that forgiveness is greater than revenge.  40  before act!
【小题1】
A.to    B.ofC.inD.from
【小题2】
A.comes B.came   C.has come D.is
【小题3】
A.happy  B.unhappy  C.happily   D.luckily
【小题4】
A.too   B.veryC.so    D.such
【小题5】
A.it    B.her    C.heD.him
【小题6】
A.poor   B.lucky   C.bad    D.small
【小题7】
A.came out B.came down C.calmed downD.calmed out
【小题8】
A.school  B.hospital   C.shopD.home
【小题9】
A.breakB.breakingC.brokenD.broke
【小题10】
A.stood upB.got upC.woke up  D.put up
【小题11】
A.how   B.whereC.why   D.when
【小题12】
A.felt    B.fell     C.sounded  D.looks
【小题13】
A.anyone  B.everyoneC.no oneD.someone
【小题14】
A.repair   B.repaired   C.be repaired D.be repairing
【小题15】
A.To think B.ThinkingC.Think   D.Be thought
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