Someone left their bag here.
Refers to an unspecified person.
Someone is knocking at the door.
Someone should help her with that.
Someone will call you back.
someone special
someone else
someone important
somebody
anyone
a person
I met someone interesting today.
A person, often used in a general sense.
С мощным бесплатным словарём с картинками и флэшкартами.