To change the focus of a sentence. In the passive sentence above, we can make the object and action ('me' and 'gave a prescription') more important than the subject ('the doctor').
Grammar and Tenses
If we don't know who does an action. "My bicycle has been stolen" - I don't know who has stolen it.
Grammar and Tenses
If we don't want to say who did something. "The lights were left on all night." (I don't want to say that you left the lights on.)
Grammar and Tenses
If it is obvious who does something. "I was given a prescription" - I know that only doctors give prescriptions, so I don't need to add "by the doctor". "He was arrested" I know that the police arrest people, so I don't need to add "by the police".
Grammar and Tenses
Forming a passive sentence in English
Firstly, you need to make the object into the new subject. me - I you - You him / her - He / She us - We them - They
Grammar and Tenses
Then you make the verb passive. Put the verb "to be" into the same tense as the verb in the active subject. For example "gave" is the past simple tense. The past simple form of "to be" is "was" or "were". Present simple - is /are Present continuous - is / are being Present perfect - has / have been Simple past - was / were Past continuous - was / were being Modals will, can etc - will be, can be etc.
Then add the past participle of the verb. For example "gave" - "given".
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