Three kids have been learning chemistry for only a few months. But they have already begun to challenge (挑战) a world famous scientist!
Li Weichi, Huang Runling, and Xiao Yan are from Zhongshan Huaqiao Middle School in Guangdong. They have just found a red cabbage that could be a new kind of acid-base indicator (酸碱指示剂). They want it to take the place of litmus (石蕊) paper.
We’ve learnt to think of and ask questions about life by ourselves, said Li, We work well with each other.
British scientist Robert Boyle discovered the use of litmus paper over 300 years ago. Now it is used widely in experiments all over the world.
But when the kids did some experiments in class last winter, they saw that the litmus paper didn’t turn very blue with base matter. It’s hard to get a clear result.
Will there be a better indicator than litmus paper? The three kids decided to try and find out!
How? They went to collect over 40 plants in parks, gardens and markets. Then they ground (研磨) leaves, flowers and stems (茎) to get the pigments (色素) from them.
The kids mixed pigments with acid and base. They spent months watching carefully to see which paper showed the best colour change. They decided it was the litmus paper!
It’s our first scientific journey, Huang said, But it makes me want to try harder.
【小题1】 Whom did the three kids want to challenge?A．Their chemistry teacher.B．Their headmaster.C．Robert BoyleD．Thomas Edison【小题2】 From the text, a red cabbage is a kind of .A．plantB．animalC．paperD．liquid【小题3】What is widely used as the acid-base indicator now?A．red cabbageB．litmus paperC．any plantD．any flower【小题4】The story mainly tells us .A．how to make litmus paperB．about the three kids’ spiritC．scientists were wrongD．the kids are heroesC
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(答案→)C
解析：
本文讲的是三个中学生入挑战世界闻名的科学家Robert Boyle使用石蕊纸的事，告诉我们做事要有一种坚持的精神。
1. C 答案来自于本句：British scientist Robert Boyle discovered the use of litmus paper over 300 years ago，属于对细节的理解，选C，其它几项未说到。
2. A 此题属于推理题，要联系上下文才能找到答案。从下文They went to collect over 40 plants in parks, gardens and markets可知是一种植物plant,故选A。
3. B 对细节题的考查。在Now it is used widely in experiments all over the world中的it指代的就是上方说到的litmus paper，故正确答案为B。
4. B 本题是个归纳总结题。文章从他们三个决定挑战到后面努力收集寻求的过程，说明他们三个的精神的可贵，这也是这篇文章的主旨所在，选B。