阅读下面这篇短文，短文后有2项测试任务：(1)第23～26题要求从所给的6个选项中为规定段每段选择1个正确的小标题；(2)第27—30题要求从所给的6个选项中选择4个正确选项，分别完成每个句子。
Hepatitis is a disease characterized by inflammation of and injury to the
liver. The disease has many causes, including misuse of alcohol and drugs, but
viruses are the most common cause. Researchers estimate that more than 300,000
cases of viral hepatitis occur each year in the United States.
2. Symptoms of viral hepatitis appear from two weeks to six months after
exposure to the virus. The first symptoms are usually fatigue, poor appetite,
and nausea. Pain in the abdomen above the liver and a slight fever are also
common. After a few days, the person’s urine becomes dark and jaundice appears.
The jaundice and dark urine indicate the liver is not working
properly. 3. Symptoms of viral hepatitis generally last two to
six weeks. Severe cases can lead to liver failure and death. But most
patients-even those with severe hepatitis-eventually recover completely. In some
patients, the disease becomes persistent and is called chronic hepatitis. People
with chronic hepatitis may experience mild, vague symptoms of fatigue and poor
appetite. 4. There are five types of viral hepatitis. Hepatitis
A is a highly contagious disease, but it is rarely fatal. It is also called
infectious hepatitis. Hepatitis A is extremely common in developing nations.
Outbreaks often occur due to unsanitary conditions, such as contamination of
food or the water supply. 5. Hepatitis B is the best-known form
of viral hepatitis. It can be severe and often develops into chronic hepatitis.
Hepatitis B is spread by close personal or sexual contact with an infected
person, or by exposure to infected blood. 6. Hepatitis C is usually spread by
exposure to infected blood. It is the most common cause of transfusion-related
hepatitis. It is also a common cause of chronic hepatitis. Hepatitis D is the
most serious and also the rarest form of viral hepatitis. It only infects people
who also have hepatitis B. Many cases of hepatitis D are fatal, and most
commonly occur among intravenous drug users, who can be infected by sharing
hypodermic needles. Hepatitis E often occurs in epidemics that can be linked to
poor hygiene and contaminated water. It is particularly likely to lead to
serious illness in pregnant women. The disease has been reported almost
exclusively in developing countries. Paragraph 2______.