|(13a)||The school board gave||the teachers||a raise.|
|(14a)||The exchange student bought||her hosts||a thank-you gift.|
Because such verbs have two objects they are called ditransitive verbs, in contrast with the monotransitive VT verbs. There is no generally accepted label to distinguish this verb type from ordinary monotransitive verbs, so we will label them VD.
Verbs that allow this two-noun-phrase pattern often have an alternate form where a prepositional phrase serves the same function as the indirect object:
(13b) The school board gave a raise to the teachers.
(14b) The exchange student bought a thank-you gift for her hosts.
Many grammar books label these prepositional phrases indirect objects, but technically they are not. The prepositional phrases here play the same semantic role as the equivalent indirect objects, a role known as the recipient, but remember that semantic roles differ from grammatical roles. Recipient is a semantic role, indirect object is a grammatical role. A verb can only be VD if it is followed by two noun phrases. If it is followed by only one NP, it is an ordinary monotransitive (VT) verb.
Ditransitive verbs can be made passive just like monotransitive ones. The passive forms of ditransitive verbs move one object into the subject position and leave the other in the original place. Usually, however, it is the indirect rather than the direct object that is moved. Moving the direct object typically sounds slightly strange:
(15a) Teachers were given a raise by the school board.
(15b) ?A raise was given the teachers by the school board.
 Notice that our logic here in distinguishing indirect objects from PPs with the same semantic role is exactly parallel to the uncontroversial treatment of by-phrases in passive sentences (e.g., "John was kicked by Bob"). There, the by-phrase expresses the role of the actor, the same role played by the subject in the active equivalent ("Bob kicked John"). But no one would call by Bob the grammatical subject of the passive sentence. That role is filled by John.