It has been in use since 1998. (划线提问)
           it              in use?
I don’t like winter because it is too cold.（划线提问）
like winter?
To be a good student is quite difficult. (改为同义句)
difficult to              a good student.
Daniel bought a new printer. (改为被动语态)
A new printer                                       Daniel.
I spent much time buying books. （改为同义句）
It              me much time                           books.