问题 单项选择题 A1/A2型题

将白血病分为急性和慢性两大类的最主要依据是()。

A.贫血程度

B.出血程度

C.白血病细胞的类型

D.白血病细胞的数量

E.白血病细胞的成熟程度

答案

参考答案:E

解析:本题考点是白血病的分类。根据白血病细胞的成熟程度和自然病程,将白血病分为急性和慢性两大类;根据主要受累的细胞系列可将急性白血病分为急性淋巴细胞白血病和急性非淋巴细胞白血病。慢性白血病则分为慢性粒细胞白血病和慢性淋巴细胞白血病以及少见类型的白血病,如毛细胞白血病、幼淋巴细胞白血病等。

单项选择题
阅读理解

阅读理解。

     Sorry to say, our brains naturally start slowing down at the Cruelty young age of 30. It used

to be thought that this couldn't be helped, but new studies show that people of any age can train

their brains to work faster. "Your brain is a learning machine," says University of California scientist

Dr. Michael Merzenich. Given the right tools, we can train our brains to act like they did when we

were younger. All that's required is the practice designed just for the purpose: a few exercises for

the mind.

    Merzenich has developed a computer-based training method to speed up the process(过程)in

which the brain deals with information  ( positscience. com). Since much of the data we receive

comes through speech, the Brain Fitness Program works with language and hearing to better

speed and accuracy (准确性).

     Over the course of training, the program starts asking you to distinguish (辨别) sounds (between

"dog" and "bog", for example) at an increasingly faster speed. It's a bit like tennis instructor, says

Merzenich, hitting balls at you-faster and faster to keep you challenged(受到挑战).

You may start out slow, but before long you're pretty quick,

    The biggest finding in brain research in the last ten years is that the brain at any age is highly plastic.

If you ask your brain to learn, it will learn. And it may even speed up while in the process.

     To keep your brain young and plastic you can do one of a million new activities that challenge and

excite you: playing table tennis or bridge, doing crossword puzzles, learning a language. . . "When

it comes to preventing ageing, you really do ' use it or lose it' ,"says Barbara Sahakian, professor at

Cambridge University.

1. Dr. Merzenich's training method mainly depends on_________.    

A. speech training

B. computer languages

C. the activities one joins in

D. the information being dealt with

2. By saying"the brain at any age is highly plastic", the writer probably means the brain can be_____.  

A. used                          

B. mastered

C. developed                      

D. researched

3. What can we learn from the text?  

A. Practice makes a quick mind.

B. Brain research started ten years ago.

C. Dr. Merzenich is a scientist in computer.

D. People believed nothing could stop the brain slowing down.

4. Which of the following agrees with the writer's idea?

A. The training methods work better for the old.

B. People should use the brain to stop it from ageing.

C. The training of the brain should start at an early age.

D. It's necessary to take part in as many activities as possible.