[填空题]The progress of technology makes it possible for the middle classes to derive more pleasure from gardening which only the rich had once afforded.

[填空题]The progress of technology makes it possible for the middle classes to derive more pleasure from gardening which only the rich had once afforded.

[单项选择]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, mos