試題詳解

38. How is it assumed that the virus of the deadly disease found its way into the United States?
(A) an infected passenger traveled from Africa to the U.S.
(B) an infected African doctor came to work in a U.S. hospital
(C) a U.S. citizen picked up the virus while in Africa.
(D) an infected mosquito or bird was transported from Africa to the U.S.