Passive voice of intransitive verbs

Solution 1:

This is not as complicated as it seems.

What you are looking at here is called a Prepositional Passive (PP or P-passive), which is sometimes referred to as a pseudo-passive. In this form, the complement of a preposition is realised as the subject of a passivised verb, as in your examples.

In

He laughed at me ~ I was laughed at (by him)

The complement of the preposition phrase at me becomes the subject I - which is why it changes - of the passivised verb (was) laughed.

Solution 2:

A verb may have both a transitive and an intransitive function, depending on how it is used. Furthermore, transitive verbs and verbs with verb phrase complements may be conjugated in the passive voice.

When intransitive verbs are used with prepositions (laugh at, listen to, work on etc...), are they considered as transitive verbs?

To answer your question, yes sometimes but this is not why they are considered transitive verbs.

A prepositional verb consists of a transitive verb plus a preposition with which it is closely associated. A verb phrase complement completes the meaning of a verb or a verb phrase.

In each of the examples you have presented, a verb is used with a prepositional phrase as a verb phrase complement. Additionally, as you see in the following example, the word 'laughed' is used as a transitive verb together with the preposition 'at' to form the prepositional verb 'laughed at'. The object is 'me'. Also, the verb 'laughed' is completed by the verb phrase complement 'at me'.

He laughed at me.

At whom did he laugh? the object = me / verb phrase complement = at me

Alternatively,

I was laughed at by him

The conjugated verb here is 'was laughed at' and the verb phrase complement is 'by him'.

Who was laughed at by him? original object = I

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the-simple-present-passive-of-english-verbs

the-verb-phrase-complement-in-english-grammar

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