29.(1)Why does the woman know where Beijing Aeronautics University(北京航空航天大學) is? A.Because she has taken a train near it. B.Because it's near her living place. C.Because she is studying in it. (2)What do we know about the man? A.He has climbed the Great Wall once. B.He shows great interest in the Great Wall. C.He.doesn't know how to get to the Great Wall. (3)What does the woman think of climbing the Great wall? A.She thinks it can be inspiring. B.She thinks it must be thrilling. C.She thinks it can be dangerous.
30.(1)What did the United States Army want medical experts to do? A.To know more about mosquitoes. B.To stop yellow fever from spreading. C.To find out what disease the soldiers had got. (2)How many researchers developed yellow fever before Doctor Lazear? A.2. B.7. C.9. (3)What did Doctor Lazear prove? A.Mosquitoes could spread yellow fever. B.The soldiers didn't die of yellow fever infections. C.Young men were more likely to develop yellow fever. (4)What did the researchers do after Doctor Lazear's death? A.They immediately went back to America. B.They turned their attention to other insects. C.They chose to put their lives at risk for the research.