4、The bumpy（凹凸不平的）structure of walnuts is similar to the brain．Some Chinese believe　eating walnuts will make them smarter because of that．By the same logic，they believe eating pig brains will increase their intelligence．This kind of food myth is true to Americans，too. Some Americans regularly eat uncooked eggs to keep their minds sharp．

       Most doctors don’t recommend eating either raw eggs or animal brains．Then, what food is good for your brain? Scientists have found a relationship between diet and a healthy brain．It’s becoming pretty clear that the right food can increase brain power―help you pay attention, keep you motivated，improve memory, and defuse stress．Perhaps even prevent brain aging．

       The health of your brain depends not only on how much（or little）fat you eat but on what kind it is．Intellectual performance requires the specific type of fat found most commonly in certain fish．Besides oily fish，you should introduce lots of dark green leafy vegetables and colorful fruits into your diet．Most people lack the special vitamins that these brain foods provide．

But you won’t do well on your test just because you ate fish the night before. You must eat brain foods regularly．

 

48．Which of the following is closest in meaning to the underlined word “defuse” in Para. 2?

A．Confuse.            B．Avoid.                C．Lessen.              D．Feel.
49．Which of the following is needed if people want to strengthen their brain power?

       A．Brain-shaped foods                             B．Uncooked eggs．

       C．Fat of any kind                                   D．Certain vegetables．

50．Which of the following statements can be supported by the passage?

A．The author must be good at cooking.
    B．Good marks only depend on regular brain foods.
    C．Neither walnuts nor animal brains really help increase mental power.
    D．Americans believe eating uncooked eggs makes them more clever than having      

Walnuts.
51．The author reminds the readers__________________________．

A．of the importance of tests                      B．to have brain food regularly
    C．never to eat fish before tests                   D．of the danger in eating unhealthy food