Gerund and Gerundive
[37.] 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. [§ 406. 1].
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. [§ 406. 2].
[38.] The accusative of the gerund or gerundive with ad, or the genitive with causā, is used to express purpose. [§ 407].
[39.] Primary tenses are followed by primary tenses, and secondary by secondary. [§ 358].
[40.] The subjunctive is used in a dependent clause to express the purpose of the action in the principal clause. [§ 349].
[41.] A substantive clause of purpose with the subjunctive is used as object with verbs of commanding, urging, asking, persuading, or advising, where in English we should usually have the infinitive. [§ 366].
[42.] Verbs of fearing are followed by a substantive clause of purpose introduced by ut (that not) or nē (that or lest). [§ 372].
[43.] Consecutive clauses of result are introduced by ut or ut nōn, and have the verb in the subjunctive. [§ 385].