填空题

Questions 47 to 56 are based on the following passage.
There is progress toward a possible treatment for lung diseases such as SARS ( severe acute respiratory syndrome ). Researchers have learned more about how the SARS virus works: it (47) with a system in the body that uses enzymes (酶) to control blood pressure and fluid balance. Scientists say the virus (48) to an enzyme known as ACE-two. The virus blocks the enzyme, permitting fluid to enter the lungs.
A team from Europe and Asia reported the (49) in Nature Medicine. Doctor Josef Penninger of the Institute of Molecular Biotechnology in the Austrian Academy of Sciences was the (50) writer of the report. The discovery could lead to a new (51) of treating not just SARS but also other diseases that can cause lung failure. These include avian flu (禽流感) and influenza in humans.
The first (52) of SARS were discovered in Guangdong province, in southern China, in November of 2002. SARS was not (53) as a worldwide threat until March of 2003. The disease spread to 26 countries, most of them in the Asia-Pacific area. An estimated 8 000 people had SARS. More than 770 of them died, or about 10% , a (54) high rate.
The World Health Organization warned people not to travel to (55) areas. The (56) hurt international travel and business. The WHO says the disease stopped spreading by July of 2003. As a result of SARS, the health agency got new powers to act before a government officially announces a crisis.

• A) means
• B) alternative
• C) attaches
• D) crisis
• E) cases
• F) associates
• G) major
• H) awful
• I) relatively
• J) findings K) optimistically L) identified
  M) interferes N) distributed O) affected