地下鉄は地面の下を走る。

underground train; subway

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

ground; earth's surface

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

below; down; under; younger (e.g. daughter); bottom; beneath; underneath; just after; right after; inferiority; one's inferior (i.e. one's junior); trade-in; preliminary; preparatory

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.

to run; to travel (movement of vehicles); to drive; to hurry to; to retreat (from battle); to take flight; to run away from home; to elope; to tend heavily toward