De acuerdo con el texto, some, half, most y all...
The subject pronouns, like she or it or they, refer to specific, definite persons, places, or things. However, indefinite pronouns do not refer to a specific person or place or to definite things. Indefinite pronouns, such as the words some, half, most, and all, may take either singular or plural verbs, depending on their meaning in the context of the sentence. If these words tell how much of something is meant, the verb is singular; but if they tell how many of something is meant, the verb is plural. Students should not confuse the words with the words each, either, and neither. Those three words always require a singular verb.