a) A Noun or Pronoun; as,—
puer scrībit, the boy writes;
hīc scrībit, this man writes.
b) An Infinitive; as,—
decōrum est prō patriā morī, to die for one's county is a noble thing.
c) A Clause; as,—
opportūnē accīdit quod vīdistī, it happened opportunely that you saw.
2. A Personal Pronoun as Subject is usually implied in the Verb and is not separately expressed; as,—
scrībō, I write; videt, he sees.
a. But for the purpose of emphasis or contrast the Pronoun is expressed; as,—
ego scrībō et tū legis, I write, and you read.