Active and passive voice Rule with modals

Modals	Auxiliary Verb in Passive Voice	Active Voice	Passive Voice
Can/ Could	Can/Could+ be+ 3rdverb	I can solve these sums.	These sums can be solved by me.
		I cannot solve these sums.	These sums cannot be solved by me.
		Can I solve these sums?	Can these sums be solved by me?
Has to/ Have to	Has to/ Have to+3rdverb	He has to complete his assignment.	His assignment has to be completed by him?
Must	Must+3rd verb	You must learn this book.	This book must be learnt by you.
May	may+be+3rd verb	I may buy the book.	The book may be bought by me.
Might	might+ be+ 3rd Verb	They might play chess.	Chess might be played by them.
Should	should+ be+3rd verb	Students should learn all lessons.	All lessons should be learnt by students.