彼らは次々に立って出ていった。

they (usually male); them

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

in succession; one by one

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

to stand; to rise; to stand up; to find oneself (e.g. in a difficult position); to depart (on a plane, train, etc.)

to leave; to exit; to go out; to come out; to get out; to leave (on a journey); to depart; to start out; to set out; to move forward; to come to; to get to; to lead to; to reach; to appear; to come out; to emerge; to surface; to come forth; to turn up; to be found; to be detected; to be discovered; to be exposed; to show; to be exhibited; to be on display; to appear (in print); to be published; to be announced; to be issued; to be listed; to come out; to attend; to participate; to take part; to enter (an event); to play in; to perform; to be stated; to be expressed; to come up; to be brought up; to be raised; to sell; to exceed; to go over; to stick out; to protrude; to break out; to occur; to start; to originate; to be produced; to come from; to be derived from; to be given; to get; to receive; to be offered; to be provided; to be presented; to be submitted; to be handed in; to be turned in; to be paid; to answer (phone, door, etc.); to get; to assume (an attitude); to act; to behave; to pick up (speed, etc.); to gain; to flow (e.g. tears); to run; to bleed; to graduate