Modal verbs in English express notions such as obligation, possibility, permission, and ability, varying according to the communicative context. Consider the sentence: "Students ___ wear uniforms at this school; it is a mandatory rule." Choose the alternative that presents the modal that expresses obligation and appropriately fills the gap.

The passive voice in English is formed by the verb "to be" in the tense corresponding to the active voice, followed by the past participle of the main verb. Consider the active sentence: "The team will finish the project next week." Choose the alternative that presents the correct form of the sentence in the passive voice.

Irregular verbs in English present specific forms in the simple past and in the past participle, not following the regular pattern of the "-ed" ending. Considering this characteristic, choose the alternative that correctly presents the past participle of the verb "go", used in the structure of the present perfect tense.

Verb tenses in English express different temporal and aspectual relations, indicating when and how an action occurs. Consider the sentence: "By the time the teacher arrived, the students had already finished the activity." The verb tense used in the second clause expresses: