（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：                                  。

教师节快到了，请你自己设计并制作一张贺卡，送给老师。

 

 

 

 

 

 

 

教师节快到了，请你自己设计并制作一张贺卡，送给老师。

 

 

 

 

 

 

 

使用下面的对话套语，调查你的同学所喜爱的学科、原因及该学科的任课教师，并做好记录。

　　A: What's your favorite subject?

　　B: My favorite subject is English.

　　A: Who is your English teacher?

　　B: Mr Li is my English teacher.

　　A: Why do you like English?

　　B: Because it's useful and interesting.

　　听下面一段独白并回答问题：

　　录音材料

　　Hello, everyone. You're welcome to Xi'an. I'm your guide. Well, first let me tell you something about the city. You know, ladies and gentlemen, Xi'an was one of the greatest cities in the world. It used to be called Chang'an, and now it is the capital of Shanxi Province. Xi'an is well－known for its history. There are many places of attraction for you to see, such as Banpo Village, Terracotta Warriors, and so on. Banpo Village is the oldest village in China and was discovered in 1953. Let me see, er, twenty－one years later, the Terracotta Warriors were discovered by a farmer digging a well. Now it is famous all over the world. Uhm, your hotel is in the centre of Xi'an. Right, let's go to the hotel first.

1．Who did the speaker speak to?

[　　]

A．Farmers.　　B．Passengers.　　C．Visitors.

2．How many places of attraction did the speaker mention in his speech?

[　　]

A．One.　　　B．Two.　　　C．Three.

3．When were the Terracotta Warriors discovered?

[　　]

A．In 1952.　　　B．In 1974.　　　C．In 1970.

4．Where are the people going to stay first?

[　　]

A．In Banpo Village.

B．In a large hall.

C．In the middle of the city.