Don’t forget the book to the library when you finish it.
A. to give back ; to read
B. to return ; reading
C. returning ; reading
D. returning ; to read
网友回答
A. to give back ; to read
(答案→)B. to return ; reading
C. returning ; reading
D. returning ; to read
解析：考查动词固定搭配。Forget to do sth忘记要做某事；forget doing sth忘记做了某事；finish doing sth做完某事；句意：当你读完这本书的时候，不要忘记把这本书还给图书馆。根据句意是指“忘记要做某事”“forget to do sth”；故B正确。