completing a complementary infinitive
agrees in gender, number, and case with the subject of the main
verb.

Mali pueri esse boni non possunt, _bad boys are not able to_
(or _cannot_) _be good._

Observe that /boni\ agrees with /pueri\.

_216._ The Infinitive used as a Noun. In English the infinitive is
often used as a pure noun, as the subject of a sentence, or as a
predicate nominative. For example, _To conquer_ (= conquering) _is
pleasing; To see_ (= seeing) _is to believe_ (= believing). The same use
of the infinitive is found in Latin, especially with /est\, as

Superare est gratum, _to conquer is pleasing_
Videre est credere, _to see is to believe_

_a._ In the construction above, the infinitive often has a subject,
which must then be in the accusative case, as

Galbam superare inimicos est gratum multis,
_for Galba to conquer his enemies is pleasing to many_

_b._ An infinitive used as a noun is neuter singular. Thus, in the
sentence /superare est gratum\, the predicate adjective /gratum\ is
in the neuter nominative singular to agree with /superare\ the
subject.

_217._ EXERCISES

First learn the special vocabulary, p. 291.

I. 1. Magister ludi liberos cum diligentia laborare iussit. 2. Egere
cibo et vino est viris molestum. 3. Viri armati vetuerunt Gallos castra
ibi ponere. 4. Estne legatus in castello an in muro? Is est pro porta.
5. Ubi nostri[1] fugere inceperunt, legatus ab vestris[1] captus est.
6. Galli castellum ibi oppugnaverant ubi praesidium erat infirmum.
7. Alii pugnare temptabant, alii portas petebant. 8. Feminae pro
domiciliis sedebant neque resistere validis Gallis poterant.
9. Bellum est saevum, nec infirmis nec miseris favet. 10. Sed viri arma
postulabant et studebant Gallos de muris agere. 11. Id castellum ab
Gallis occupari Romanis non gratum erit. 12. Galli ubi a Romanis victi
sunt, esse liberi[2] cessaverunt. 13. Diu sine aqua vivere non potestis.

II. 1. The girl began daily to carry water from the river to the gates.
2. The Gauls had pitched their camp in a place suitable for a battle.
3. For a long time they tried in vain to seize the redoubt. 4. Neither
did they cease to hurl weapons against[3] the walls. 5. But they were
not able to (could not) take the town.

[Footnote 1: Supply _men_. /nostri\, /vestri\, and /sui\ are often
used as nouns in this way.]

[Footnote 2: Not _children_. The Rom