Forming Passives With Modals

Affirmative Form	Object + may, must, can, could, ought to, should + be + verb3
Question Form	Must, may, can, should, might + object + be + verb3 (past participle)

Something must / can / should... be done by someone at sometime.

Active : Our English teacher may give an exam today.
Passive: An exam may be given by our English teacher today.

Active : Thomas has written many books.
Passive: Many books have been written by Thomas.

Active : Do you have to pay the bill before leaving the restaurant?
Passive: the bill have to be paid before leaving the restaurant?

Active : Juan can give them some information about the job.
Passive: Some information can be given about the job by Juan.
Passive2: They can be given some information about the JOB by Juan.

Active : You must obey the traffic rules.
Passive: The traffic rules must be obeyed.

Quick Exercise

Put the following sentences into passive voice. (Modals)

1. We may ask him a few questions. 
2. I can manage a motor car. 
3. You must inquire the way. 
4. He might give you a chance. 
5. I could show you his house if you would permit me. 
6. I should enjoy a sea-voyage.