An intransitive construction is a type of sentence structure where the verb does not require a direct object to complete its meaning. In these sentences, the action is performed by the subject, but there is no recipient of that action. For example, in the sentence "The baby sleeps," the verb "sleeps" does not act upon anything; it simply describes what the subject, the baby, is doing. Intransitive verbs can also be followed by adverbial phrases or prepositional phrases that provide additional information, but these do not change the intransitive nature of the verb. For instance, in "The dog barked loudly," the verb "barked" remains intransitive, as it does not take a direct object, even though "loudly" adds detail about how the action is performed.