Questions 56 to 60 are based on thefollowing passage．
　　Scientists at Washington University School of Medicine in the US found higher levels of protein S1PR2(磷酸鞘氨醇受体蛋白)in tests on the brains of female mice and dead women with MS than in male equivalents．Four times more women than men are currently diagnosed with Multiple Sclerosis(多发性硬化症)．
　　Experts said the finding was”really interesting”．MS affects the nerves in the brain and spinal cord，which causes problems with muscle movement，balance and vision．It is a major cause of disability,and affects about 1 00，000 people in the UK．Abnormal immune cells aRack nerve cells in the central Nervous system in MS patients．There is currently no cure，A.though there are treatments that can help in the early stages of the disease．
　　Researchers in Missouri looked at relapsing remitting(复发缓解型)MS，where people have distinct attacks of symptoms that tllen fade away either partially or completely．About 85％of all people with MS have this type．Scientists studied the blood vessels and brains of healthy mice，mice with MS，and mice without the gene for SlPR2，a blood vessel receptor protein，to see how it affected MS severity．They A.so 100ked at the brain tissue samples of 20 people after they had died．They found high levels of S1PR2 in the areas of the brain typically damaged by 　　MS in both mice and people．Tlle activity of the gene coding for S1 PR2 was positively correlated with the severity of the disease in mice．the study said．
　　Scientists said S l PR2 could work by helping to make the blood-brain barrier,in charge of stopping potentiA.ly harmful substances from entering the brain and spial fluid．more permeable．A more permeable barrier could let attacking cells，which cause MS，into the central nervous system，the study said．This link[between MS and S lPR2] is completely new一it has never been found before．
　　Dr Emma Gray,of the MS Society,said：”We don’t yet fully understand why MS affects more women than men,and it’s an area that’s intrigued scientists，and people with MS，for many years．She said understanding the causes of MS was a“priority”for the MS Society in the UK．and could be“crucial”in finding new treatments．
56．What can we infer from the last sentence in Para．1 ?
A. Wbmen are more likely to be diagnosed with Multiple Sclerosis．
B.Men are more likely to be diagnosed with Multiple Sclerosis．
C.Male mice are more likely to be diagnosed with Multiple Sclerosis．
D、FemA.e mice are more likely to be diagnosed with Multiple Sclerosis．
57．What problem does MS mainly cause?
A.In natured muscle movement．
B.Bad bA.ance．
C. Disability
D.Bad eyesight．
58．What is the relationship between the severity ofMS and level ofSlPR2?
A. A.The level of S 1 PR2 is higher,the MS is less severe．
B.The level of S 1PR2 is higher,the MS is more severe．
C. The level of S 1 PR2 is lower,the MS is less severe．
D、The level of S 1 PR2 is lower,the MS is more severe．
59．What role does SlPR2 play in helping the permeability ofblood．brain barrier?
A.It can make blood．brain barrier impermeable．
B.It can make blood—brain barrier less permeable．
C.It can make blood—brain barrier permeable．
D.It can make blood—brain barrier more permeable．
60．What can we infer from the whole passage?
A.Four times more women than men are currently diagnosed with MS．
B. The level of S 1 PR2 was positively correlated with the severity of MS．
C.The reason why MS affects more women than men is unknown．
D.Multiple sclerosis discovery may explain gender gap．

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