Well, verbs are not inherently singular, per se. That is, the endings on the verbs, specifically Present tense verbs, tell us whether the subject is singular or plural. For the most part, only the 3rd person singular of Present tense verbs carries an overt number/agreement marker. Like this,Originally Posted by stressin
Notice the verb swim has an -s only with singular subjects She, He, and It.
As for the verb BE, Present tense, we have to learn the forms because they are irregular. That is, they don't follow a pattern like swim:
As for the verb BE, Past tense,
Again, we have to learn the forms.
As for the future, BE is regular, so we won't have to learn the forms:
The verb HAVE is as follows:
PRESENT: I have, You have, She has, He has, It has, They have, You have, We have
Notice the -s (She has, He has, It has).
PAST: I had, You had, She had, He had, It had, They had, You had, We had.
Hope that helped out some. :D