56. The author of the passage advises us _____.
    A. to use words carefully and accurately
    B. not to use silly and rude words
    C. to become a slave of words
    D. to use emotional words

                                    E
    If you want to stay young，sit down and have a good think. This is the research finding of a team of Japanese doctors, who say that most of our brains are not getting enough exercise, and as a result，we are ageing unnecessarily soon.
Professor Taijiu Matsuzawa wanted to find out why otherwise healthy farmers in northern Japan appeared to be losing their ability to think and reason at a relatively early age, and how the process of ageing could be slowed down.
    With a team of partners at Tokyo National University，he set about studying the brain volumes（体积）of a thousand people of different ages and various jobs.
    Computer technology enabled the researchers to get exact measurement of the volume （容量）of the front and side sections of the brain，which relate to intellect（智能）and feelings，and determine the human character. The back section of the brain，which controls functions like eating or breathing，does not connect with age. One can continue living without intellectual or feeling abilities.