The long O sound, /o/, can be spelled many ways.  Typically, it is spelled with an O as in no, go, most.  It can also be spelled:

O:  no

OE:  toe

OA:  oath

EAU:  beau

OW:  snow

OUGH:  dough

AOH:  pharogh

AU:  chauffer

EW:  sew

OO:  brooch

OU:  shoulder

OT:  depot