問題詳情
【題組】19.The author discusses ducks in order to providean example of birds that
(A) grow replacement feathers that are very long
(B) shed all their wing feathers at one time
(C) keep their innermost feathers
(D) shed their outermost feathers first
參考答案
答案：B
難度：非常困難0
統計：A(1),B(0),C(3),D(0),E(0)