The Modal Passive

 Structure: MODAL + BE + PAST PARTICIPLE (+BY+NOUM)

Ex. The computer should be repaired.

https://www.youtube.com/watch?v=0COmUBQmzeg

http://www.learnamericanenglishonline.com/Green%20Level/G8%20Modal%20Passive.html

http://www.studyandexam.com/passive-voice-for-modal.html