15．What is stroke？Stroke is a typical disease which occurs when a blood clot（凝塊）blocks an artery（動(dòng)脈） or a blood vessel（血管） breaks，interrupting blood flow to an area of the brain．When either of these things happens，brain cells begin to die and brain damage occurs．Abilities controlled by that area of the brain are lost such as speech，movement and memory．Some people recover completely from strokes，but more than 2/3 of survivors will have some type of disability．Anyone can have a stroke regardless of men and women．it is really imperative for us to know something about Stroke Risk Factors．Risk factors are some beyond our control such as over age 55，being male，being Chinese，or having a family history of stroke．Others are controllable．Stroke prevention guidelines were brought forth by Journal of the American Medical Association 1n 1999．These includes：
46．Paragraph 1 is meant to sayA．
A．people can reduce the happening chances of storke
B．a(chǎn) stroke victim is bound to die or become disabled
C．middle-aged Chinese meales are sure to have storke
D．stroke is not as dangerous as most people may think
47．The underlined word"imperative"here meansB．
A．wonderful
B．necessary
C．valuable
D．supportive
48．From Item 5 we can infer thatC．
A．both LDL and HDL are bad cholesterols in human body
B．human body does not need such a thing as cholesterol
C．high cholesterol can be controlled with diet and exercise
D．people without LDL will be healthier than those who have
49．What will contribute to the danger of a stroke？D
A．Drinking some wine daily
B．Walking 30 minutes a day
C．Cutting down on salt and fat
D．Losing temper constantly
50．The best title for this passage isD
A．What is Stroke？
B．Ten Causes of Stroke
C．Stroke and Health
D．How to Prevent Stroke．
