Breakdown of gakusei ha eiga wo mimasu.

Questions & Answers about gakusei ha eiga wo mimasu.
学生 is pronounced がくせい (gakusei), meaning “student.”
映画 is えいが (eiga), meaning “movie.”
見ます is みます (mimasu), the polite present tense of “to see/watch.”
見ます is the polite non-past form, covering both present and future (e.g. “watches” or “will watch”).
To make it past tense, say 見ました (mimashita).
To make it negative, say 見ません (mimasen).
は marks the topic or contrasts information, so 学生は… sets “student” as the theme.
が marks the grammatical subject or highlights new/important information. Using 学生が映画を見ます might emphasize “it is the student (not someone else) who watches the movie.”
見ます is the masu-form (polite) you’d use in formal or respectful contexts.
見る is the plain or dictionary form, used in casual speech, writing, or when listing verbs in a dictionary.