Причиной перевода информационных ресурсов человечества на электронные носители является:

1. New words are always written by us into our exercise books.
2. Every text is followed by exercises.
3. The school library is used by the pupils.
4. The school uniform isn't worn by all pupils.
5. All the text-books are given to us by the teacher. We are given all the text-books by the teacher.
5. My clothes are washed by my mother.