I will never forget the hours we spent ______ English books in the library.

1. A.
   to read
2. B.
   reading
3. C.
   read
4. D.
   readed

I will never forget the hours we spent ____ English books in the library.

    A. to read   B. reading   C. read   D. readed 

I will never forget the hours we spent ____ English books in the library.