Latin Verbs:

mood: indicative, subjunctive, imperative, infinitive

tense: present, imperfect, future // perfect, pluperfect, future perfect

UNFINISHED (present system) 

present:- what is going on now or is; 
          Melissa cantat. Melissa sings, is singing, does sing.
        - an action begun in the past and
          still going on now (jam, jam diu, dudum, pridem);
          Tres jam horas adsum. I have been here for three hours.
        - instead of perfect tense;
          Caecilius in culinam pavonem portat et cantat. Caecilius brought a peacock to the kitchen and singed.
imprerfect:- what went on or was for a long time;
             Puer lacrimabat et infelix erat. The boy was crying and was unhappy.
           - repeated action in the past; 
             Prima luce surgebat. He used to get up at dawn.
           - attempted action in the past;
             Puer arborem ascendebat. The boy tried to climb the tree.
           - an action begun in the past and
             still continuing at the time mentioned (jam,jam diu, dudum,pridem);
             Tres jam horas aderam. I had been present for three hours (and still was present).
future: - what is going to happen or will be;
          Epistola longa erit. The letter will be long.
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FINISHED (perfect system)

perfect: - 'once' action in the past;
           Veni, vidi, vici. I came, I saw, I conquered. 
         - the present result of a past action;
           Pontem fecerunt. The have built the bridge.
pluperfect: - an action already completed before another action in the past;
              Regem occiderant priusquam pervenimus. They had killed the king before we arrived.
future perfect: -an action which will take place before another actin in the future;
                 Si redieris, poenas dabis. If you return, you will be punished.

number: singular, plural

person: 1^st, 2^nd, 3^rd

verbal adjective: participle

verbal noun: gerund, supine

Four Stems: 

present stem (1), present active infinitive (0), perfect stem (2), participial stem (3).