Your search for the postposition -ni in, during has returned 4 entries

-ni

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in, during

-ni

Na’ahóóhaii Ya’iijááshtsoh bini góne’ nída’adleeh.

July 3-in 3-into rodeo 3-Pl-SUP-be.R
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In July, rodeo events take place.

Yas Niłt’ees bini góne’ yas dajiłhį́į́h.

January 3-in 3-into snow Pl.4-melt.I
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In January you melt snow.