The verb tense indicates the time at which the action of the verb takes place. Past tense verbs, for example, tell us that the action took place in the past. Present tense indicates the action is happening at this very moment, or that it happens regularly in the present state of things, or that it is true up to the present moment. In Passive Constructions. A form of the verb “To be” is combined with a past participle to form the passive. Passive verb constructions are useful when the subject of an action is not as important as what the subject did (the action of the sentence) or when the subject is unknown.