81. From the theme of leadership for World AIDS Day, we can infer that ____.

1. advances over the past 20 years have benefited from leadership of nations
2. governments should promise to take universal action to prevent and treat AIDS
3. the leaders of each nation should take responsibility for preventing and treating AIDS
4. the leaders of each nation have taken powerful new medications for treating AIDS

82. The most-affected area of AIDS is ____.

1. Africa
2. United States
3. wealthy nations like France
4. not mentioned

83. By saying "There is no single magic bullet for HIV prevention," Peter Piot means that ____.

1. AIDS cannot be prevented or cured easily
2. experts focus on taking many tests to help HIV from spreading
3. scientists are forced to abandon two clinical trials for an AIDS vaccine
4. experts tried best to shatter a magic bullet for preventing HIV last year

84. Which of the following can be seen as a big step in preventing and treating HIV?

1. The United Nations urged countries to focus on the roots of HIV.
2. A pair of scientists discovered HIV.
3. Researchers have discovered new molecules.
4. U.S. scientists recently discovered a gene for vaccine.

85. The biggest challenges of AIDS today are the following EXCEPT ____.

1. affordable and effective treatment remains rare in poor countries
2. universal access to medication is not likely to be realized recently
3. an effective vaccine has not been found yet
4. those with HIV can not enjoy the same lifespan as those without

(Reference keys.)