问题补充：
------- you the book to the library yet.
------ Yes. I have.
A. Have ，returned，/
B. Have， returned， back
C. Did return ，/
D. Did， return，back
答案：
(答案→)A. Have ，returned，/
B. Have， returned， back
C. Did return ，/
D. Did， return，back
解析：根据答句Yes，I have 推测应选用助动词have；归还sth 可以表达为 return sth to……或者 give sth back to……
