--Have you returned the book to the library ?Yes I have returned it.A. yet yet B. al

问题补充：

--Have you returned the book to the library ? --Yes, I have returned it.

A. yet, yet

B. already, already

C. already, yet

D. yet, already

答案：

A. yet, yet

B. already, already

C. already, yet

(答案→)D. yet, already

解析：句意：你已经把这本书还给图书馆了吗？是的我已经归还了。yet用于疑问句，已经，用于否定句，还；already,用于肯定句，已经。故选D