4. (15.0分) Thousands of infants become infected with the AIDS virus every year.These boys and girls are born to mothers who have HIV, the human Immunodeficiency virus. Infection takes place during pregnancy or from breastfeeding. Recently, scientists identified a protein in breast milk that suppresses the virus, and may even protect babies from becoming infected. Now, experts say the discovery could lead to new ways to protect babies whose mothers are infected with HIV.To prevent infection, doctors give anti-retroviral drugs (抗逆转录病毒药) 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 percentage of babies become infected through breast milk.Sallie Permar is a professor of pediatrics (儿科) and immunology (免疫学) at Duke University Medical Center. She says the protein found in breast milk is called Tenascin-C. It works by blocking the virus from attaching to cells in the baby's body.(单选题 3分) How does Tenascin-C work to protect babies from HIV?A It stops the virus from attaching to the baby's cellsB It kills the HIV virus directly in the mother's bodyC It reduces the amount of breast milk the baby drinksD It increases the baby's ability to produce anti-AIDS drugs<|im_end|>(单选题) How does Tenascin-C work to protect babies from HIV?A It stops the virus from attaching to the baby's cellsB It kills the HIV virus directly in the mother's bodyC It reduces the amount of breast milk the baby drinksD It increases the baby's ability to produce anti-AIDS drugs

4. (15.0分) Thousands of infants become infected with the AIDS virus every year.These boys and girls are born to mothers who have HIV, the human Immunodeficiency virus. Infection takes place during pregnancy or from breastfeeding. Recently, scientists identified a protein in breast milk that suppresses the virus, and may even protect babies from becoming infected. Now, experts say the discovery could lead to new ways to protect babies whose mothers are infected with HIV.To prevent infection, doctors give anti-retroviral drugs (抗逆转录病毒药) 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 percentage of babies become infected through breast milk.Sallie Permar is a professor of pediatrics (儿科) and immunology (免疫学) at Duke University Medical Center. She says the protein found in breast milk is called Tenascin-C. It works by blocking the virus from attaching to cells in the baby's body. (单选题 3分) How does Tenascin-C work to protect babies from HIV? A It stops the virus from attaching to the baby's cells B It kills the HIV virus directly in the mother's body C It reduces the amount of breast milk the baby drinks D It increases the baby's ability to produce anti-AIDS drugs <|im_end|> (单选题) How does Tenascin-C work to protect babies from HIV? A It stops the virus from attaching to the baby's cells B It kills the HIV virus directly in the mother's body C It reduces the amount of breast milk the baby drinks D It increases the baby's ability to produce anti-AIDS drugs