Final answer:
A sentence is written in the passive voice when the subject has something done to it, often indicated by the use of a 'be' verb form and a past participle, with or without a 'by' phrase indicating the doer of the action.
Step-by-step explanation:
For a sentence to be written in passive voice, it requires that the subject has something done to it, rather than being the doer of the action. This can be identified when a sentence meets certain criteria:
- The subject is acted upon by the verb.
- A form of the 'be' verb (am, is, are, was, were) is used together with the past participle of the main verb.
- The preposition 'by' followed by a noun phrase is present in the sentence or can be logically added to indicate who or what is performing the action.
For example, the sentence 'That his house was no place for a dance party was argued by Jose.' in the passive voice would be 'Jose argued that his house was no place for a dance party.' in the active voice.