What's the pre-masu (verbs left in pre-masu) form in Japanese used for?

Question:

A lot of Japanese texts use a form so that the verbs end in -re several times. For example, "tsukurare", "ari", and "hairi". From context, I figure this to be similar to the "te" form in terms of usage but could someone clarify what this form is used for and what its called? Thanks.

Answer:

I think I understand your question.
As far as I remember, "-masu" form and "-te" form (called 'gerundive') are both called "連用形 renyou-kei (Attributive form)" and when it comes to conjugation they do NOT have ALWAYS the same stem. (see *note below)
The following site would be helpful.　Go to 5 Conjugable words --> "Stem form" and "Verb" to look at Conjugation Table.
http://en.wikipedia.org/wiki/Japanese_gr…

* note;
tsukau: tsukat-te (tsukai-te is NG) --> tsukai-masu
kaku: kai-te --> kaki-masu
asobu: ason-de --> asobi-masu
gambaru: gambat-te --> gambari-masu