阅读下列短文,从每题所给的A、B、C和D项中,选出最佳选项。-|||-Hundreds of thousands of children become infected with the AIDS virus every year.These boys-|||-and girls are born to mothers who have HIV.Infection takes place during pregnancy(怀孕) or-|||-from breastfeeding.-|||-Recently,scientists found a protein in breast milk that stops the virus.The protein may even-|||-protect babies from becoming infected.Now,experts say the discovery can lead to new ways to-|||-protect babies whose mothers are infected with HIV.-|||-To prevent infection,doctors give anti AIDS drugs to both mothers and their babies. That-|||-has greatly reduced the number of infections. But experts say that even without anti-AIDS drugs,-|||-only a small part of babies become infected through breast milk.Sallie Permar is a professor at-|||-Duke University in North Carolina.She says breast-fed babies appear to resist(抵抗)infection.-|||-The low rate of infection was of great interest to researchers,including Sallie Permar.She led-|||-the effort to find something in breast milk that may protect babies from infection.Her team-|||-directed its attention to a protein called Tenacin-C.also called TNC.It is known to help heal-|||-wounds.However,what purpose it serves in breast milk is unknown.-|||-The researchers exposed the TNC protein from breast milk of uninfected women to HIV.The-|||-protein made it harmless.Anti-AIDS drugs remain effective in limiting the passing of HIV from-|||-mothers to babies.But Professor Permar and her team suggest that TNC should be used in places-|||-where costly drug treatments are often not available.It can help infected people there save money-|||-and reduce their pain.She suggests that TNC should be given to babies before breastfeedi to-|||-provide additional protec against HIV.She adds that the protein is safe because it is already a-|||-natural part of of human milk.-|||-41.Pregnant women who have been infected with HIV usually __ _-|||-A.decide not to breastfeed their babies-|||-B.choose not to give birth to their babies-|||-C.don`t worry about their unborn babies-|||-D.get their unborn babies infected with it-|||-42.From Paragraph 3,we learn that anti-AIDS drugs __-|||-A.don`t work well on breast fed babies-|||-B.don`t work very well on pregnant women-|||-C.can definitely better protect the babies than breast milk-|||-D.are very effective in keeping babies from getting HIV-|||-43.We know that the protein called Tenacin-C __-|||-A.is a newly found protein-|||-B.does well in healing wounds-|||-C.can only be found in breast milk-|||-D.isn`t very important in breast milk-|||-44.Compared with anti-AIDS drugs sold on the market now, TNC is much __-|||-A.less costly-|||-B more popular-|||-C.more efficient-|||-D.less dangerous-|||-45.What is the main idea of the passage?-|||-A.Anti-AIDS drugs are used to limit the spread of HIV.-|||-B.People are no longer fearful of HIV around the world-|||-C.Numerous children become infected with HIV every year.-|||-D.A protein in breast milk has been found to fight against HIV