单项选择题
Diseases have diverse causes, which can be classified into two broad groups: infectious and noninfectious. Infectious diseases can spread from one person to another and are caused by microscopic (极小的) organisms that invade the body. Noninfectious diseases are not communicated from person to person and do not have, or are not known to involve, infectious agents. Some diseases, such as the common cold, are acute, coming on suddenly and lasting for no more than a few weeks. Other diseases, such as arthritis (关节炎), are chronic (长期的), persisting for months or years, or recurring (复发) frequently.
Every disease has certain characteristic effects on the body. Some of these effects, called symptoms and signs, include fever, inflammation, pain, fatigue, dizziness, nausea, and rashes, and are readily apparent to the patient. These symptoms offer important clues that help physicians and other health care professionals make a diagnosis. Many times, however, the symptoms point to several possible disorders. In those cases, doctors rely on medical tests, such as blood examinations and X rays, to confirm the diagnosis.
The course of a disease--that is, the path it follows from onset to end--can vary tremendously, depending largely on the individual and the treatment he or she receives. For example, otherwise healthy people usually recover quickly from a bout of pneumonia (肺炎) if given proper treatment, whereas pneumonia often proves fatal to people with a weakened immune system and to those who do not receive prompt, effective treatment. Some diseases run a different course depending on the patient’s age. Chicken pox (水痘), for instance, is usually mild in childhood but severe in adults. In the United States, only about 5 percent of chicken pox cases occur in people over the age of 20, but these cases account for 50 percent of all deaths from the disease.
A.be saved
B.recover
C.50 percent be cured
D.none of the above is correct