Medical care has three main elements: diagnosis of disease or injury, treatment of dise

ase or injury, and prevention of disease.

2. Serious ailments require diagnosis by an expert, who, in most cases, is a doctor. Doctors use three main types of "clues" in making a diagnosis: the patient's case history, the doctor' s physical examination of the patient, and the results of medical tests. Patients provide their own medical history by answering questions about their physical condition and past illnesses. Doctors use medical instruments, such as a stethoscope to listen to a patient's heart and lungs, to perform. a physical examination. Medical laboratories aid diagnosis by making chemical and microscopic tests on body fluids and tissues. A physician may also order tests that use X rays, sound waves or electric waves to detect disease by literally looking inside the body.

3. People usually recover from minor illnesses and injuries without special treatment. In these cases, doctors may simply reassure their patients and allow the body to heal it-self. But serious ailments generally require special treatment. In these cases, a doctor may prescribe drugs, surgery, or other treatment. For thousands of years, drugs and surgery have provided two of the chief methods of treating disease. But modern science has helped make these methods much more effective than they used to be. Penicillin aad other "wonder drugs" help cure many infectious diseases that were once extremely difficult to treat. With the help of machines, surgeons can repair or replace organs that have been seriously damaged, including the heart and kidneys. Science has also helped develop entirely new methods of treatment. Radiotherapy, for example, makes use of X-rays and radioactive rays to treat cancer.

4. Doctors help prevent disease in various ways. They may give vaccinations to guard against such diseases as polio, hepatitis, and measles. They may also order a special diet or drug to strengthen a patient's natural defenses against illness. People can also help themselves remain healthy by exercising, by not smoking, and by avoiding use of alcohol or illegal drugs. Doctors can prevent many diseases from becoming serious by diagnosing and treating them in their early stages. For this reason, most doctors recommend regular physical examinations.

5. Local governments also contribute to the prevention of disease. They do sc by enforcing public health measures. For instance, they make sure that the community has pure drinking water and a system of garbage and sewage disposal. A number of national and international organizations work to improve the quality of medical care. These organizations encourage medical education and research, help standardize medical practice, and enforce codes of professional conduct.

A. Diseases to different extent can be treated in many kinds of method

B. A doctor's diagnosis may include the patient's case history, the doctor's physical examination of the patient and the results of medical tests

C. Some diseases used to be incurable

D. Doctors may use many different methods as an assistance to the prevention of disease

E. Local governments also make their contribution to the prevention of disease

F. Radiotherapy is an entirely new machine used to treat cancer

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