Polio, although it is eradicated in the United States, it continues elsewhere and is able to be brought into the country by visitors.
(A) Polio, although it is eradicated in the United States, it continues elsewhere and is able to be
(B) Polio, although eradicated in the United States, it still continues elsewhere and can be
(C) Although still continuing elsewhere, polio has been eradicated in the United States and could be
(D) Although having been eradicated in the United States, polio still continues elsewhere and is capable of being
(E) Although eradicated in the United States, polio continues elsewhere and could be
答案是E，但是为什么continues 可以和could并存？
