第三部分：概括大意和完成句子（第23~30题，每题1分，共8分）
下面的短文后有2项测试任务：（1）第23~26题要求从所给的6个选项中为指定段落每段选择1个小标题；（2）第27~30题要求从所给的6个选项中为每个句子确定一个最佳选项。
Multiple Sclerosis（多发性硬化症）
1 Multiple Sclerosis (MS) is a disease in which the patients immune（免疫的）system attacks the central nervous system. This can lead to numerous physical and mental symptoms, as the disease affects the transmission of electrical signals between the body and the brain. However, the human body, being a flexible, adaptable system, can compensate for some level of damage, so a person with MS can look and feel fine even though the disease is present.
2 MS patients can have one of two main varieties of the disease: the relapsing form （复发型）and the primary progressive form. In the relapsing form, the disease progresses in a series of jumps; at times it is in remission（减轻）.which means that a persons normal functions return for a period of time before the system goes into relapse and the disease again becomes more active. This is the most common form of MS; 80-90% of people have this form of the disease when they are first diagnosed. The relapse-remission cycle can continue for many years. Eventually, however, Ioss of physical and cognitive functions starts to take place and the remissions become less frequent.
3 In the primary progressive form of MS, there are no remissions and a continual but steady loss of physical and cognitive functions takes place. This condition affects about 10-15% of sufferers at diagnosis.
4 The expected course of the disease, or prognosis（预后）,depends on many variables: the subtype of the disease, the patients individual characteristics and the initial symptoms. Life expectancy of patients, however, is often nearly the same as that of an unaffected person - provided that a reasonable standard of care is received. In some cases a near-normal life span is possible.
5 The cause of the disease is unclear; it seems that some people have a genetic Susceptibility（易感性）,which is triggered by some unknown environmental factor. Onset（发作）of the disease usually occurs in young adults between the ages of 20 and 40.It is more common in women than men; however, it has also been diagnosed in young children and in elderly people.
23. Paragraph 1___E___
24. Paragraph 2 __B____
25. Paragraph 3___D___
26. Paragraph 4____F__
A. The cause of MS
B. The relapsing form of MS
C. The treatment for MS
D. The primary progressive form of MS
E. The definition of MS
F. The development of MS
27. MS affects the communication of nerve cells between the body and ___E___
28. An MS patient can feel fine for years without being affected much by ___A___
29. 10-15% of MS patients are diagnosed as having ___C___
30. Young adults might have a higher chance of developing the disease than ___B___
A. relatives of MS patients
B. the elderly people
C. the disease
D. the progressive form
E. the brain
F. life expectancy