The name-form is also used with various auxiliaries (may, might, can, must, will, should, shall, etc.) to assert futurity, determination, possibility, possession, etc. Examples: I may go, We shall come, You can see, Horses should run.
By preceding it with the word to, the name-form is used to form what is called the Present Infinitive; as, I wish to go, I hope to see.
What may be called the s-form of the verb, or the singular form, is usually constructed by adding s or es to the name-form. The s-form is used with singular subjects in the third person; as, He goes, She comes, It runs, The dog trots.
The s-form is found in the third personal singular of the present tense. In other tenses, if present at all, the s-form is in the auxiliary, where the present tense of the auxiliary is used to form some other tense of the principal verb. Examples: He has (present tense), He has gone (perfect tense), He has been seen.
Some verbs have no s-form; as, will, shall, may. The verb be has two irregular s-forms: Is, in the present tense, and was in the past tense. The s-form of have is has.
52. The past tense always stands alone in the predicate; i. e., it should never be used with any auxiliaries. To use it so, however, is one of the most frequent errors in grammar. The following are past tense forms: went, saw, wore, tore. To say, therefore, I have saw, I have went, It was tore, They were wore, would be grossly incorrect.
53. The third principal part, the past participle, on the other hand, can never be used as a predicate verb without an auxiliary. The following are distinctly past participle forms: done, seen, sung, etc. One could not then properly say, I seen, I done, I sung, etc.
The distinction as to use with and without auxiliaries applies, of course, only to irregular verbs. In regular verbs, the past tense and past participle are always the same, and so no error could result from their confusion.
The past participle is used to form the Perfect Infinitives; as, to have gone, to have seen, to have been seen.
54. The following is a list of the principal parts of the most important irregular verbs. The list should be mastered thoroughly. The student should bear in mind always that, the past tense form should never be used with an auxiliary, and that the past participle form should never be used as a predicate verb without an auxiliary.