Are the following intransitive verbs, or transitive verbs?

Question

1. When using Cognate objects. eg. "I dreamt a strange dream". Is the verb intransitive because 'dreamt' doesn't need the object here, or is it a Transitive because we have an object for the verb.
2. When adding preposition. eg. "All his friends laughed at him" - Transitive or Intransitive and why?
3. When using Adverbial object. eg. "The watch cost nine hundred dollars". - Transitive or Intransitive and why?

Answer 1

I dreamt a strange dream.

The verb dream can be used as a noun, transitive verb, or intransitive verb. In the above sentence, it's a transitive verb; the subject is I and the direct object is "a strange dream". The sentence, though grammatically correct, sounds old-fashioned. Usually, you say "I had a strange dream.

All his friends laughed at him.

The phrasal verb in the sentence is a transitive verb; the subject is "all his friends and the direct object is "him".

The watch cost nine hundred dollars.

The verb is transitive; the subject is "the watch" and the direct object is nine hundred dollars.

Answer 2

There is more more category of verbs other than what you described -transitive, intransitive, and both! It depends how you use it.

All my references are from the OALD

So, in your examples:

"I dreamt a strange dream - the use of 'dream something' there in sense #2

"laugh at somebody" seems an idiom - but anyway, transitive

The watch cost nine hundred dollars - transitive.

Answer 3

At in Laugh at is not a preposition. It is a particle in the phrasal verb laugh at.

Laugh at is always transitive, and therefore any sentence in the active voice written with laugh at must have a direct object, as in

0 All his friends laughed at him.

The verb is laugh at. The direct object of the verb is him.

Without a direct object for laugh at, the sentence is ungrammatical. For example:

00 *All his friends laughed at.

This sentence is ungrammatical. There is no direct object for the verb laugh at, which is always transitive.

Another way to say that the verb laugh at is "always transitive" is to say that it is always used transitively or that it is always used with a direct object. When we say that the verb laugh at is not transitive, we mean that it cannot be used intransitively (it cannot be used without a direct object (see Sentence 00)).

This is different from the verb stand by The verb stand by can be either transitive or intransitive. Another way to say this is that the verb stand by can be used either transitively (with a direct object) OR used intransitively (without a direct object). Below, in Sentences 3b and 6b, stand by is transitive, or used transitively (that is, with a direct object). In Sentences 2 and 4, stand by is intransitive or used intransitively (these are just two different ways of saying that stand by is used without a direct object). In Sentences 1a, 1b, 3a, and 6a, the verb is stand. It is used intransitively in 1a, 3a, and 6a. It is used transitively in 1b.

In the sentence:

1a An old beggar stood by the gate.

The verb is stood. The word by is a preposition and it is part of the prepositional phrase by the gate. The word by is not part of the verb.

Note that in stand (past tense: stood) can also be used as a transitive verb, that is, it can be used transitively (with a direct object). An example of this is

1b The old beggar by the gate could not stand the heat.

(Stand here means endure.)

In

2 The old beggar stood by.

Stood by in this sentence is intransitive (that is, it is used intransitively), as there is no direct object. And by is not a preposition but a particle of the phrasal verb stand by.

Now, note that the sentence

3 The old beggar stood by me

is ambiguous. It can be analyzed two ways. It can be analyzed as containing the verb stand (3a) or stand by (3b).

3a The old beggar stood by me.

The verb is stand and in this sentence it is intransitive, or used intransitively, and by me is a prepositional phrase (the preposition is by and me is the object of the preposition).

3b The old beggar stood by me.

The verb is stand by (transitive). Here me is the direct object of the verb stand by. By is a particle in the phrasal verb stand by. In this sentence, by is not a preposition.

Note you could also have:

4 The old beggar stood by by the gate.

Here stand by is again intransitive, where the first by is a particle of the phrasal verb stand by, and the second by is the preposition in the prepositional phrase by the gate.

To get a little bit more complicated, look at Sentence 6:

6 The old beggar stood by me by the gate.

What is the verb in Sentence 6? Well, just like Sentence 3, Sentence 6 can be analyzed two ways: with the verb as either stand (6a) or stand by (6b).

6a The old beggar stood by me by the gate.

In 6a, the verb is stand (past tense: stood). It is intransitive or used intransitively. These are two ways of saying that the verb stand is not used with a direct object in this sentence. Note that this sentence, there are two prepositional phrases: by me and by the gate. Both uses of by are as a preposition.

6b The old beggar stood by me by the gate.

In this case, the verb is stand by (past tense: stood by). It is used transitively, that is, with a direct object. The direct object of stand by is me. And by the gate is the only prepositional phrase in the sentence. In the sentence, the first by is not a preposition, it is a particle; it is part of the verb stand by (past tense: stood by). The second by is functioning as a preposition in the prepositional phrase by the gate.