(3) That the gerundive, being an adjective, is used only in agreement with a noun.
[406.] Rule. Gerund and Gerundive. 1. The Gerund is a verbal noun and is used only in the genitive, dative, accusative, and ablative singular. The constructions of these cases are in general the same as those of other nouns.
2. The Gerundive is a verbal adjective and must be used instead of gerund + object excepting in the genitive and in the ablative without a preposition. Even in these instances the gerundive construction is more usual.
[407.] Rule. Gerund or Gerundive of Purpose. The accusative of the gerund or gerundive with ad, or the genitive with causā3 (= for the sake of), is used to express purpose.
| Gerund | Gerundive |
|---|---|
| Ad audiendum vēnērunt or Audiendī causā vēnērunt They came to hear | Ad urbem videndam vēnērunt or Urbis videndae causā vēnērunt They came to see the city |
3. causā always follows the genitive.
Note. These sentences might, of course, be written with the subjunctive of purpose,—vēnērunt ut audīrent; vēnērunt ut urbem vidērent. In short expressions, however, the gerund and gerundive of purpose are rather more common.
[408.] We have learned that the word denoting the owner or possessor of something is in the genitive, as, equus Galbae, Galba’s horse. If, now, we wish to express the idea the horse is Galba’s, Galba remains the possessor, and hence in the genitive as before, but now stands in the predicate, as, equus est Galbae. Hence this is called the predicate genitive.
[409.] Rule. Predicate Genitive. The possessive genitive often stands in the predicate, especially after the forms of sum, and is then called the predicate genitive.
[410.] IDIOMS