There are variations in the way verbs form the past tense. They can be looked at in the following way: ...

For example, the tense may change between the methods section and the discussion section. The abstract is usually in the past tense due to it showing what has already been studied. Example: “This ...

Form the perfect tense using the auxiliary verb 'haber' and a past participle. Irregular verbs in the perfect tense in Spanish The perfect tense is made of the verb 'haber' and a past participle.