Most of the auxiliary verbs are defective in conjugation; that is, they are used only in some of the moods and tenses; and when unconnected with principal verbs, they are conjugated in the following manner: 

MAY. 
Pres.  Tense Sing.  I may, thou mayst, he may.
            Plur.  We may, ye or you may, they may.

Imperf. Sing.  I might, thou mightst, he might. 
Tense. Plur.  We might, ye or you might, they might.

CAN. 
Pres. Sing.  I can, thou canst, he can. 
Tense. Plur.  We can, ye or you can, they can.

Imperf. Sing.  I could, thou couldst, he could. 
Tense. Plur.  We could, ye or you could, they could.

WILL. 
Pres. Sing.  I will, thou wilt, he will. 
Tense. Plur.  We will, ye or you will, they will.

Imperf. Sing.  I would, thou wouldst, he would. 
Tense. Plur.  We would, ye or you would, they would.

SHALL. 
Pres. Sing.  I shall, thou shalt, he shall. 
Tense. Plur.  We shall, ye or you shall, they shall.

Imperf. Sing.  I should, thou shouldst, he should. 
Tense. Plur.  We should, ye or you should, they should.

TO DO. 
Pres. Sing.  I do, thou dost or doest, he doth or does. 
Tense. Plur.  We do, ye or you do, they do.

Imperf. Sing.  I did, thou didst, he did. 
Tense. Plur.  We did, ye or you did, they did.
          Participles.  Pres. doing.  Perf. done.

TO BE. 
Pres. Sing.  I am, thou art, he is. 
Tense. Plur.  We are, ye or you are, they are.

Imperf. Sing.  I was, thou wast, he was. 
Tense. Plur.  We were, ye or you were, they were.
          Participles.  Pres. being.  Perf. been.

TO HAVE. 
Pres. Sing.  I have, thou hast, he hath or has. 
Tense. Plur.  We have, ye or you have, they have.

Imperf. Sing.  I had, thou hadst, he had. 
Tense. Plur.  We had, ye or you had, they had.
          Participles.  Pres. having.  Perf. had.

Do, be, have, and will, are sometimes used as principal verbs; and when employed as such, do, be, and have, may be conjugated, by the help of other auxiliaries, through all the moods and tenses.

DO.  The different tenses of do, in the several moods, are thus formed:  Indicative mood, pres. tense, first pers. sing.  I do; imperfect tense, I did; perf.  I have done; pluperfect, I had done; first future, I shall or will do; sec. fut.  I shall have done.  Subjunctive mood, pres. tense, If I do; imperf. if I did; and so on.  Imperative mood, do thou.  Potential, pres.  I may, can, or must do, &c.  Infinitive, present, to do; perf. to have done.  Participles, pres. doing; perf. done; compound, having done.