。
She studies English.
Literal
She [topic-は] English [object-を] studies.
A bare polite habitual sentence. With no time adverb, 勉強します could in principle mean 'will study' or 'studies (regularly).' Standalone like this, the habitual reading is the default for activity verbs in present tense — 'she studies English (as something she does).' The same form 勉強する is used in casual speech; the ~ます ending is what marks the polite register.