443. The stem has in general a double form

1. Participles in ant or at.

The stem has in general a double form, a stronger and a weaker, ending respectively in अन्त् ant and अत् at. The former is taken in the strong cases of the masculine, with, as usual, the nom.-acc.-voc. pl. neuter; the latter is taken by all the remaining cases.

a. But, in accordance with the rule for the formation of the feminine stem (below, 449), the future participles, and the present participles of verbs of the tud-class or accentedá-class (752), and of verbs of the ad-class or root-class ending in ā, are by the grammarians allowed to make the nom.-acc.-voc. du. neut. from either the stronger or the weaker stem; and the present participles from all other present-stems ending in a are required to make the same from the strong stem.