For it (actor -um-) to rain heavily.
dumloh; edloh
A substantive with actor role is unexpressed in the sentence.
Dinumloh ad a''u.
(It) rained heavily last night.
-um-: dumloh
For it (actor & inst) to cause rain (theme i-) to fall heavily.
Nun'albong nan payaw ti enedlohna din udan.
The pond fields were all flooded because it caused the rain to rain heavily.
A substantive with actor and instrument roles occurs only in the sentence unidentified as a pronoun -na `it'.
i-: edloh
apāli
dipappo'
dulu