Passive Voice: Verb Transformations
Visit the Passive Voice page before you read this. There's a four step process to altering a sentence from active voice to passive voice, and the last two steps can be a bit more complicated when more advanced verb strings are involved. Here's what else you need to know.
The verb phrase of passive structures can get a little tricky when it’s in other tenses like past continuous or future perfect. At least it looks confusing, but in actuality forming those sentences isn’t any more complicated.
The trick is that you always have to add to be, even if there already is a to be, which means there could be two of them, but that’s okay. The other thing to remember is that the to be you add has to be in the form that the main verb was originally in (with active voice), and it should come after all the other auxiliary verbs.
- The first auxiliary verb may need to change to agree with the new subject (which is now the passive noun). For example, “Someone has reserved these seats” changes to “These seats have been reserved.”
- Verbs (helping or main) that follow modals are in the base infinitive form, not necessarily the present simple form. Although the two forms are identical most of the time (except for the 3rd-person ‘s’), the key exception is with to be.
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- The present simple forms of to be are ‘am’, ‘is’, and ‘are’.
- The base infinitive form of to be is ‘be’. Therefore, we say ‘must be’, ‘should be’, ‘has to be’, etc.
- Past modals, on the other hand, are followed by ‘have been’.
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- Whether an adverb comes before or after to be depends on the adverb. In general (but with some exceptions):
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- Adverbs of frequency, relative time, and certainty come before the passive to be but after the other auxiliary verbs.
- Adverbs of manner and degree come after the passive to be (and after all of the aux. verbs) but before the main verb.
- Adverbs of place and of absolute time come after the main verb. Multi-word adverb phrases also come after the verb.
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- For questions, the first auxiliary verb should come before the new subject.
- There should be no do/does/did in negative and interrogative sentences (except as a main verb; to be should replace any form of do.
- ‘Not’ comes after the first auxiliary verb.