The Allen and Greenough is still under construction;
so some links may not work quite the way you would expect.
Omission of Subject or Verb.
318. The Subject of the Verb is sometimes omitted: -
a. A Personal pronoun, as Subject, is
usually omitted unless emphatic: -
- loquor, I speak.
- But, ego loquor, it is I that
b. An indefinite subject is often omitted:
- crederes, you would have supposed;
putamus, we (people) think; dicunt, ferunt, perhibent, they say.
c. A passive verb is often used
impersonally without a subject expressed or understood (§208. d): -
- diu atque acriter pugnatum est
(B. G. i. 26), they fought long and rigorously.