Although the first part of the book is easy， the rest ______.

A. are difficult                                B. has proved difficult

C. is supposed difficult                        D. have been found difficult

Although the first part of the book is easy， the rest ______.

1. A.
   are difficult
2. B.
   has proved difficult
3. C.
   is supposed difficult
4. D.
   have been found difficult

Although the first part of the book is easy， the rest ______.

Although the first part of the book is easy， the rest ______.

Although the first part of the book is easy， the rest ______.

　 A. are difficult　　　　　　　　　　　

　 B. has proved difficult　

　 C. is supposed difficult　　　　　

　 D. have been found difficult