Sentences which we cannot change into passive voice
Transitive Verb and Intransitive Verb
A verb has got two types transitive verb and intransitive verb. A transitive verb needs an object in a sentence to give complete meaning and intransitive verb does not need an object in a sentence to show complete meaning.
He Operated. (giving no meaning without object)
He operated computer. (giving complete meaning with object)
Some examples of transitive verbs. take, show, offer, leave, drive, build, teach, learn, scold, tease etc.
(smile is an intransitive verb and giving complete meaning without object.)
Some examples of transitive verbs. Sleep, go, sneeze, reach, sit, rise, die, remain, fight, live are examples of intransitive verbs.
Note: We cannot change Intransitive verb into passive voice because it gives complete meaning without object.
also see - active voice and passive voice