Using 'each other' and 'one another' for mutual actions
Subject + verb + each other / one another
Subject + don't/doesn't + verb + each other
Do they help each other?
💡 Traditionally, 'each other' = two people, 'one another' = more than two. In modern English, they're often interchangeable.
✓The two sisters help each other.
✗The two sisters help themselves.
Reciprocal (mutual action) needs 'each other', not reflexive 'themselves'.
✓They looked at each other and smiled.
✗They looked at them and smiled.
Use 'each other' for mutual action, not object pronoun.
✓We read each other's essays.
✗We read each others essays.
Possessive form: each other's (with apostrophe).