Verbs with irregular forms in the Future tense

There are a few verbs in Spanish that are irregular in the Future tense. The endings for these verbs are the same, but the stem is irregular. These verbs fall into 3 different groupings:

Group 1 - For verbs in this group, the stem remains the same, but the final vowel of the ending is dropped

saber sabr__ yo sabrécaber cabr__ yo cabréhaber habr__ yo habrépoder podr__ yo podréquerer querr__ yo querré

Group 2 - For verbs in this group, the stem remains the same, but the final vowel of the ending is dropped and replaced with a “d”

poner pondr__ yo pondrésalir saldr__ yo saldrétener tendr__ yo tendrévaler valdr__ yo valdrévenir vendr__ yo vendré

Group 3 - For verbs in this group, an entirely different stem is used

decir dir__ yo diréhacer har__ yo haré