彼はペンをおいて椅子にもたれた。

he; him; his; boyfriend

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

pen

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 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

chair; stool; post; office; position

at (place, time); in; on; during; to (direction, state); toward; into; for (purpose); because of (reason); for; with; by; from; as (i.e. in the role of); per; in; for; a (e.g. "once a month"); and; in addition to; if; although

too; also; in addition; as well; (not) either (in a negative sentence); both A and B; A as well as B; neither A nor B (in a negative sentence); even; as much as; as many as; as far as; as long as; no less than; no fewer than; even if; even though; although; in spite of; further; more; again; another; the other

to hang; to droop; to dangle; to sag; to lower; to pull down; to leave behind (at death); to give; to confer; to drip; to ooze; to trickle; to drop