Verbs have different forms to help construct subjective sentences better
The noun forms of the verb to differ are difference and the gerund, differing.
The present forms of the verb "to have" are: I have You have He/she/it has We have They have
Category is not a verb. Categorize is a verb its forms are: categorize categorizes categorized categorizing
Have is not a "to be" verb. Present tense forms of be: am/is/are Past tense forms of be: was/were Being is the present participle, and been is the past participle.
The noun forms of the verb to infect are infector, infection, and the gerund, infecting.The adjective forms of the verb to infect are infectedand infecting.
a verb
a verb
They are all singular verb forms.
The past participle forms of the verb "be" are "been" and "being".
Verb conjugation
There are three progressive verb forms in English: present progressive (am/is/are + verb-ing), past progressive (was/were + verb-ing), and future progressive (will be + verb-ing).
The verb 'was' is a helping verb. It belongs with other forms of the verb 'be'.