아도(a-do, ado)
Used after verb or adjective stems ending with the vowel 'ㅏ' or 'ㅗ', expressing 'even if' or 'although'.
When to use
Stem ends with ㅏ/ㅗ, Concessive in positive contexts, Casual conditional clause
The nuance
Attach '-아도' when the stem's last vowel is 'ㅏ' or 'ㅗ'.
어도(eo-do, eodo)
Used after verb or adjective stems ending with vowels other than 'ㅏ' or 'ㅗ', expressing 'even if' or 'although'.
When to use
Stem ends with other vowels, Concessive in negative contexts, Formal sentence construction
The nuance
Attach '-어도' when the stem's last vowel is not 'ㅏ' or 'ㅗ'.
여도(yeo-do, yeodo)
Attached to the verb '하다' to mean the same as '해도', mainly used in formal or written language.
When to use
Verb 하다 usage, Formal and literary style, Official documents or writing
The nuance
Attach '-여도' to the stem '하' of '하다' to form the same meaning as '해도'.