However, the -- for us -- self-evident distinction between past,
   present and future does not exist in the Hopi language. It makes no
   distinction between tenses, but indicates the validity a statement
   has: fact, memory, expectations or custom, There is no difference in
   Hopi between "he runs" "he is running," "he ran,' all being rendered
   by wari "running occur." An expectation is rendered by warinki
   ("running occur [I] daresay"), which covers "he will, shall, should,
   would run." If, however, it is a statement of a general law, warikngwe
   ("running occur, characteristically") is appied (La Barre, 1954, 1954,
   pp 197). The Hopi " has no general notion or intuition of time as a
   smooth flowing continuum in which everything in the universe proceeds
   at an equal rate, out of a future, through a prsent, into a past."

http://www.isss.org/primer/whorf.htm