1. She volunteered to help the children.

[Is 'volunteered' a transitive verb or an intransitive verb? In the long man dctionary, I saw "Transitive or Intransitive." What does it mean? Can 'volunteer' be a transitive verb or an intransitive verb?]

From the Longman dictionary:
volunteer2 ●●○ AWL verb 
1 [intransitive, transitive] to offer to do something without expecting any reward, often something that other people do not want to do
volunteer to do something
 Helen volunteered to have Thanksgiving at her house this year.

Yes, some verbs can be both transitive and intransitive, depending on how they're used.

Mostly, "volunteer" is an intransitive verb:

She volunteers at the local homeless shelter.
This Girl Scout troop volunteers at a nearby nursing home, mostly reading to the most elderly patients.
He volunteered to help clean up people's houses after the floods.


Sometimes it's used as a transitive verb, but this is far less frequent:

This teacher volunteered her class to pick up trash on the playground once a week.

According to the Longman dictionary, the verb "volunteer" can be both transitive and intransitive.

When a verb is described as "transitive," it means that it takes a direct object, which is the receiver of the action. For example, in the sentence "She volunteered to help the children," the verb "volunteered" is transitive, and "to help the children" is the direct object.

On the other hand, when a verb is described as "intransitive," it means that it does not take a direct object. In the same sentence, if you remove the direct object and say "She volunteered," the verb "volunteered" becomes intransitive.

Therefore, "volunteer" can be used as either a transitive verb or an intransitive verb depending on the context and the presence of a direct object.