问题 填空题

赤霉素促进茎的伸长主要与细胞壁的伸展性有关。有人进行了CaCl2和赤霉素对某植物种子胚轴生长速率影响的实验,结果如下图所示。由图分析可知,一定浓度的CaCl2溶液对细胞壁的伸展起作用;加入赤霉素溶液的时间是图中的()(A点、B点、C点)。根据上述实验分析赤霉素促进茎伸长的可能原因是()。

答案

参考答案:抑制;B点;赤霉素降低了细胞壁上Ca2+的浓度

阅读理解

V Reading

Ellas’ story

My name is Ellas .I am a poor black worker in South Africa .The time when I first met Nelson Mandela was a very difficult period of my life .I was twelve years old . It was in 1952 and he had opened a black law firm to advise black poor people on their problems .

I began school at six . The school where I studied only two years was three kilometers away. I had to leave, because my family could not continue to pay the school fees and the bus fare .I could not read or write. After trying hard ,I got a job in a gold mine, This was a time when one had got to have a passbook to live in Johannesburg. Sadly I did not have this passbook because I was not born there and I was worried about whether I would be out of work.

The day when Nelson Mandela told me what to do and helped me was one of the happiest days of my life .He told me how to get the correct papers so I could stay in Johannesburg .I never forgot how kind he was and when he organized the ANC Youth League ,I joined it as soon as I could .He said:

“The last thirty years have seen the greatest number of laws stopping our rights and progress, until today we have reached a stage where we have almost no rights at all.”

It was the truth .Black people has no vote and could not choose who ruled them .The parts of town where they lived were places decided by white people .They could not get jobs they wanted .The places there they were sent to live were the poorest areas in South Africa .No one could grow food there .In fact as  Nelson Mandela said:

“…we were put in a position in which we had either to accept we were less important ,or fight the Government .We chose to attack the law .We first broke the law in a way which was peaceful ;when this was not allowed… only then did we decide to answer violence with violence.”

As a matter of fact, I do not like violence… but in 1963 I helped him blow up some government buildings .It was very dangerous because if I was caught I could be put in prison for years .But I was happy to help because I knew it was to realize our dream of making black and white people equal.

1 Read the text and answer the following questions.

1) When and where was the writer born?

2) What difficulty did he meet when he worked in a gold mine in Johannesburg?      

3 )why did Mandela organize the ANC Youth League?      

4 )What position were the black in and what did they do

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