somebody/someone, everybody/everyone, anybody/anyone, nobody/no one
Listen! __________ is knocking at the door now.
We can't find __________ to help us with English grammar.
Listen! __________ is knocking at the door now.
We can't find __________ to help us with English grammar.
Someone and somebody
Someone and somebody have no difference in meaning. Somebody is a little less formal than someone. Someone is used more in writing than somebody. Somebody is more common in speaking.