Before revision: They are, according to some children, physically indistinguishable from real people, while others say they see their imaginary friends only in their heads, and still others cannot see the friend at all but can sense his/her presence.
After revision: They are, according to some children, physically indistinguishable from real people, while others say they see their imaginary friends only in their heads, and still others cannot see the friend at all but can sense their presence.