He went to the birthday party but forgot his present.
present
past
present participle
past participle

In the sentence:  

He went to the birthday party but forgot his present.  

Assuming the verb underlined is ‘went’ and ‘forgot’, the verb is in past tense.
Verbs are simply known as the ‘action’ words – may it be mental, physical or mechanical. When verbs are paired with auxiliaries (helping verbs), they are known as verb phrase. These helping verbs always go first before the actual verb. Perfect tenses serves a portraying the verb or the action word as something that already happened or is completed, thus the term ‘perfect’. If it is present perfect tense, it means that the action was already done relatively to the present (has/have with past participle). If it is past perfect tense, action is already finished relatively to the past (had with past participle and if it is future perfect tense, action is complete relatively to the future (will have with past participle