鍵をテーブルの上に置いてきました。行って取ってきてくれませんか。

key; lock

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.

table

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

to put; to place; to leave (behind); to establish (an organization, a facility, a position, etc.); to set up; to appoint (someone to a certain position); to hire; to employ; to place (one's trust, one's faith, etc); to bear (in mind etc); to put down a tool (e.g. a pen) hence stopping what one is doing with that tool; to take in (boarders, etc.); to provide lodging in one's house; to separate spatially or temporally; to do something in advance; to leave something in a certain state; to keep something in a certain state

to perform; to do; to conduct oneself; to carry out

to take; to pick up; to harvest; to earn; to win; to choose; to steal; to eat; to have (a meal); to remove (one's glasses, etc.); to compete (in sumo, cards, etc.); to play

indicates a question (sometimes rhetorical); or; whether or not; some- (e.g. something, someone); indicates doubt, uncertainty, etc.; emphatic prefix; suffix forming adjectives or adverbs; in that way