I mauria e ia te pukapuka, the letter was taken by him, i. e. he took the letter.
Ka haere ahau ka mau i taku pukapuka, I will go and take my letter.
§ 48. Transitive Prepositions &c. Every active verb is connected with its object, or the thing acted upon, by either of the prepositions i, or ki; some verbs requiring one, some the other, and some again taking either. These prepositions in some cases may be translated by an English preposition; but in most cases they merely represent the connexion between the verb and its object, and may therefore be called transitive prepositions.
Every passive verb is connected with the agent by the preposition "e", which is rendered "by" in English.
Examples.
Whakarongo ki nga kupu a Rewa, listen to the words of Rewa.
E matau ana ahau ki taua tangata, I know that man.
Kei te tiki ia i tana hoiho, he is fetching his horse.
I mahia e wai? by whom was it done?
§ 49. Agent emphatic. When special emphasis is to be laid on the agent an irregular construction is used, the preposition na being placed before the subject in the past tense, and ma in the future. In sentences of this kind the subject, being the most emphatic member of the sentence, stands first, and the object either before or after the verb, but without any transitive preposition. This construction is not properly used with neuter verbs.