問題詳情
15. In paragraph 1, what does the author say about the presence of a blowhole in cetaceans?
(A)It clearly indicates that cetaceans are mammals.
(B) It cannot conceal the fact that cetaceans are mammals.
(C) It is the main difference between cetaceans and land-dwelling mammals.
(D)It cannot yield clues about the origins of cetaceans.
參考答案