Here's why:
* Phrasal verbs often have an active and dynamic feel. The passive voice emphasizes the action being done *to* the subject, which contrasts with the active and often directional nature of phrasal verbs.
* The preposition in a phrasal verb can create ambiguity. In a passive sentence, the preposition would usually come after the verb "be," which can lead to confusion about the intended meaning.
Example:
* Active: The manager put off the meeting.
* Passive (awkward): The meeting was put off by the manager.
In the passive sentence, the preposition "off" is separated from the verb "put," making it sound clunky. It's better to use a different verb if possible.
Instead of using a phrasal verb in passive voice, consider these alternatives:
* Use a different verb: Instead of "put off," you could say "postponed" or "delayed."
* Rewrite the sentence in active voice: This is often the best solution, as it avoids the awkwardness of the passive voice.
Exceptions:
There are some rare cases where using a phrasal verb in passive voice might be acceptable:
* When the preposition is essential to the meaning: For example, "The project was broken down into smaller tasks."
* When the phrasal verb is idiomatic: For example, "The rumour was made up."
However, these are exceptions, and it's generally best to avoid using phrasal verbs in passive voice sentences.