把下列主动语态改为被动语态,坐等,

ecoder are often used in our english class.
a new film will be showed next week
some trees and flowers are planted(by students),括号中的也可省略,主动改被动的时候,一般动作实施者被省略
your homework must be handed before five
the boy entered room was saw (by me)
all the texts should be learned by heart
the tigers are fed three times a day at the zoo
a poem is wrriten (by him)
the light must be turned off before you go to bed
the bike is repaired by who/whom?
nothing more about this matter will be said
some flowers of silk are had made
computers are being made in the USA
rice has been grown in south china.