Questions & Answers about Mater aquam puram bibit.
Because mater is in the nominative case, which is the normal case for the subject. So mater = the mother (the doer of the action).
Because aquam is accusative singular, used here for the direct object (the thing being drunk).
- aqua = nominative (water, as a subject)
- aquam = accusative (water, as an object)
puram is an adjective meaning pure/clean, and it describes aquam. Adjectives agree with the noun they modify in case, number, and gender:
- aquam = feminine, singular, accusative
- therefore the adjective is puram = feminine, singular, accusative