In both form of sentence meaning is same only structures of words are changed. In active sentence subject is ‘’Grapes’’ object is ‘’thistles’’ and verb is ‘’gather’’. When we change into passive voice object ‘’thistles’’ will become subject and subject ‘’grapes’’ will become object. In passive form after ‘’cannot’’ ‘’be’’ will be used and verb will be written in past participle.
Active sentences in the present perfect tense have the following structure:
Subject + has/have + past participle form of the verb + object Passive sentences in the present perfect tense have the following structure: Object of the active sentence + has/have + been + past participle form of the verb + by + subject of the active sentence
