[211]. 1. The person concerned is regularly denoted by the Genitive; as,—
patris interest, it concerns the father.
a. But instead of the Genitive of the personal pronouns, meī, tuī, nostrī, vestrī, the Latin uses the Ablative Singular Feminine of the Possessive, viz.: meā, tuā, etc.; as,—
meā interest, it concerns me.
2. The thing about which a person is concerned is denoted—
a) by a Neuter Pronoun as subject; as,—
hōc reī pūblicae interest, this concerns the state.
b) by an Infinitive; as,—
omnium interest valēre, it concerns all to keep well.
c) by an Indirect Question; as,—