215. The Complementary Infinitive.  In English a verb is often followed by an infinitive to complete its meaning, as, the Romans are able to conquer the Gauls.  This is called the complementary infinitive, as the predicate is not complete without the added infinitive.

Similarly in Latin, verbs of incomplete predication are completed by the infinitive.  Among such verbs are possum\, _I am able, I can_; propero\, maturo\, _I hasten_; tempto\, I attempt; as

  Romani Gallos superare possunt,
    the Romans are able to (or can) conquer the Gauls
  Bellum gerere maturant,
    they hasten to wage war

    a. A predicate adjective 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.