Observe in each case what mood follows cum\, and try to give the reasons for its use.  In the third sentence the cum\ clause is concessive, in the fourth and sixth causal.

II. 1.  That battle was fought at the time when (tum cum) I was at Rome. 2.  Though the horsemen were few in number, nevertheless they did not retreat. 3.  When the camp had been sufficiently fortified, the enemy returned home. 4.  Since the tribes are giving hostages to each other, we shall inform Caesar. 5.  The Gauls and the Germans are very unlike in language and laws.

LESSON LXXI

VOCABULARY REVIEW :  THE GERUND AND GERUNDIVE :  THE PREDICATE GENITIVE

401. Review the word lists in Secs. 510, 511.

402. The Gerund.  Suppose we had to translate the sentence

  By overcoming the Gauls Caesar won great glory

We can see that overcoming here is a verbal noun corresponding to the English infinitive in _-ing_, and that the thought calls for the ablative of means.  To translate this by the Latin infinitive would be impossible, because the infinitive is indeclinable and therefore has no ablative case form.  Latin, however, has another verbal noun of corresponding meaning, called the gerund\, declined as a neuter of the second declension in the _genitive_, _dative_, _accusative_, and _ablative singular_, and thus supplying the cases that the infinitive lacks.[1] Hence, to decline in Latin the verbal noun _overcoming_, we should use the infinitive for the nominative and the gerund for the other cases, as follows: 

Nom.  supera:re, overcoming, to overcome   INFINITIVE
Gen.  superandi:, of overcoming            }
Dat.  superando:,  for overcoming          }
Acc.  superandum, overcoming               } GERUND
Abl.  superando:, by overcoming            }

Like the infinitive, the gerund governs the same case as the verb from which it is derived.  So the sentence given above becomes in Latin

  Superando Gallos Caesar magnam gloriam reportavit

    [Footnote 1:  Sometimes, however, the infinitive is used as an
    accusative.]

403. The gerund[2] is formed by adding /-ndi:, -ndo, -ndum, -ndo\, to the present stem, which is shortened or otherwise changed, as shown below: 

PARADIGM OF THE GERUND

CONJ.  I    CONJ.  II    CONJ.  III                CONJ.  IV
Gen.  amandi:     monendi:     regendi:     capiendi:     audiendi: 
Dat.  amando:     monendo:     regendo:     capiendo:     audiendo: 
Acc.  amandum    monendum    regendum    capiendum    audiendum
Abl.  amando:     monendo:     regendo:     capiendo:     audiendo: 

    a. Give the gerund of curo\, deleo\, sumo\, iacio\, venio\.

    b. Deponent verbs have the gerund of the active voice (see Sec.
    493).  Give the gerund of conor\, vereor\, sequor\, patior\,
    partior\.