Desist is a verb, its forms are:
base verb -- desist
third person singular -- desists
past -- desisted
past participle -- desisted
present participle -- desisting
The present forms of the verb "to have" are: I have You have He/she/it has We have They have
The verb forms of 'drop' are:To dropDropDroppedDroppingDrops
Category is not a verb. Categorize is a verb its forms are: categorize categorizes categorized categorizing
'Have' is of the verb 'to have'. 'is' is of the verb 'to be'.
A similarly-spelled verb is decease (to die), used almost exclusively as the adjective deceased (dead).Another possible word is desist (to avoid doing), used in the legal phrase "cease and desist" (stop doing and do not do again).
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.
Verb conjugation
The verb 'was' is a helping verb. It belongs with other forms of the verb 'be'.
They are different forms of the verb "to be" in the present simple tense: I am a techer. They are doctors. The verb to be most frequently works in conjunction with another verb: I am writing a letter. We are playing in the garden.These are the different forms of the verb to be for the different persons:I am, You are, He/she/it is, we are, you are, they are.