ヘリコプターが我々の上を一周した。

helicopter

indicates sentence subject (occasionally object); indicates possessive (esp. in literary expressions); but; however; still; and

we

indicates possessive; nominalizes verbs and adjectives; substitutes for "ga" in subordinate phrases; (at sentence-end, falling tone) indicates a confident conclusion; (at sentence-end) indicates emotional emphasis; (at sentence-end, rising tone) indicates question

above; up; over; elder (e.g. daughter); top; summit; surface; on; before; previous; superiority; one's superior (i.e. one's elder); on top of that; besides; what's more; upon (further inspection, etc.); based on (and occurring after); matters concerning...; as concerns ...; since (i.e. "for that reason"); suffix indicating higher social standing; place of one's superior (i.e. the throne); emperor; sovereign; shogun; daimyo; noblewoman (esp. the wife of a nobleman)

indicates direct object of action; indicates subject of causative expression; indicates an area traversed; indicates time (period) over which action takes place; indicates point of departure or separation of action; indicates object of desire, like, hate, etc.

once around; a revolution; a lap; a turn; a round; one full year