the metal statue is of a Greek soldier

of
prep.关于,...的（表所属）,出身于,由于
prep.This is a photograph of my dog.这是我的狗的一张照片.
也可以说成 This photograph is of my dog.
The metal statue is of a Greek soldier.这是一个希腊战士的金属雕像.
也可以说成This is a metal statue of a Greek soldier.
of+名词用在谓语动词后作表语,表示“……的”