11．South African researchers at the international AIDS conference in Vienna，Austria have announced major progress in the fight against the disease．The researchers say their study shows a gel（胶体）substance reduced the risk of HIV infection among women who used it．
The gel contains tenofovir，which is a common drug used to treat people with HIV，the virus that causes AIDS．
The study was done by South African scientists with the Center for the AIDS Program of Research in South Africa．Almost nine hundred sexually active women between the ages of eighteen and forty took part in it．All were from KwaZulu-Natal，South Africa．Half were given the gel containing tenofovir．The other half were given a gel without an active substance．They were told to use the gels twelve hours before having sex and again within twelve hours after having sex．
The study lasted thirty months．Women who used the tenofovir gel reduced their risk of HIV infection by thirty-rune percent．And the study found that the women who used the gel more often had even better results．Women who used the gel more than eighty percent of the times when they had sex had fifty-four percent fewer HIV infections．
Health experts say the results of the study show that tenofovir gel can empower women．However，researchers say they will study why the gel did not protect in all cases．Some scientists say the amount of tenofovir in the gel may be too low．Others say some women may have had sex with infected men who had very high amounts of the virus．The researchers also say they will carry out more studies to confirm the results．
29．What's the main idea of for the passage？C
A．South African researchers find a use for tenofovir．
B．Researchers have an international AIDS conference in Vienna．
C．Researchers in South Africa announce progress in fight against AIDS．
D．South African researchers are doing their best to protect women．
30．What can we know from the passage？D
A．The tenofovir gel works on both men and women．
B．The more tenofovir gels a woman uses，the better it is．
C．Tenofovir has never been used to fight against AIDS before．
D．Taking the tenofovir gel may protect a woman from HIV virus．
31．Researchers still don't know whyB．
A．the tenofovir gel can empower women
B．the tenofovir gel does not protect in all cases
C．the amount of tenofovir in the gel is so low
D．some men have very high amounts of HIV virus．
分析 在奥地利维也纳召开的国际艾滋病会议上，南非研究人员宣布他们在应对艾滋病的战争中取得了重大进展．研究人员表示，使用了阴道凝胶物质的女性感染HIV的风险降低．
解答 29．C．主旨归纳题．本文讲述了南非研究人员宣布他们在应对艾滋病的战争中取得了重大进展，使女性感染HIV的风险降低．故选C．
30．D．细节理解题．由第一段The researchers say their study shows a gel（胶体）substance reduced the risk of HIV infection among women who used it，可知使用了阴道凝胶物质的女性感染HIV的风险降低，故选D．
31．B．理解推断题．由最后一段However，researchers say they will study why the gel did not protect in all cases，研究人员表示，他们将会研究为什么这种凝胶不能在所有的案例中都能起到免疫作用．故选B．
点评 科教类文章理解难度偏大，因此考生可以先阅读题干要求，在带着问题阅读原文，没有对应题目的语段可直接略过，加快阅读速度，也方便做题．
