For example, if I want to say "I helped my uncle yesterday", how would I say it?
Or, I would just use the particle を.
Japanese Language Stack Exchange is a question and answer site for students, teachers, and linguists wanting to discuss the finer points of the Japanese language. It only takes a minute to sign up.Sign up to join this community
'昨日私のおじさんをてつだいました' is the correct one.
Also as a side note, '昨日おじさんをてつだいました' would be more usual (without '私の') if the helper is 'I'.