Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
occupy [ˈɔkjupaɪ] vt занима́ть (заня́ть*perf) (country, attention) захва́тывать (захвати́ть*perf)
to occupy o.s. (with sth) занима́ться (заня́ться perf) (чем-н)
all of the rooms are occupied все ко́мнаты за́няты
he was occupied with his work он был за́нят рабо́той
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.