I'll return the book to the library as soon as I_ __it .I'll returnthe book to the library as soon as I_ __it .A willfinish B am going to finish Cfinished D have finished

I'll return the book to the library as soon as I_ __it .I'll returnthe book to the library as soon as I_ __it .A willfinish B am going to finish Cfinished D have finished
I'll return the book to the library as soon as I_ __it .
I'll returnthe book to the library as soon as I_ __it .
A willfinish B am going to finish Cfinished D have finished

I'll return the book to the library as soon as I_ __it .I'll returnthe book to the library as soon as I_ __it .A willfinish B am going to finish Cfinished D have finished
选D
理由 按正常理解,书现在没看完,看完应当是将来的动作,应当用will have finished
但是还有一个主将从现原则,所以要去掉从句中的will,用 have finished.
供参考.