optional; voluntary; arbitrary; arbitrary
to hold in one's arms; to carry in one's arms; to have (problems, debts, etc.); to take on (a responsibility); to employ; to have (on one's staff)
system; lineage; corollary; system (range of strata that correspond to a particular time period); (taxonomical) series
ring; circle; hoop; wheel; circle (e.g. of friends)
whole (body); full-length (e.g. portrait); systemic
restriction; restraint; limitation; limit
scenery; scene; landscape
magnification; enlargement; expansion; amplification
order; system; structure; set-up; organization; organisation
to be imminent; to loom; to be approaching; to be impending
speck; dot; point; only a little; particle; only one
sky; air; ether; firmament; the heavens
star (usu. not including the Sun); planet (usu. not including Earth); star (glyph, symbol, shape); star (actor, player, etc.); small dot; spot; star point (in go)
repeatedly; over and over again; several layers deep; layer upon layer; row upon row
to pile up; to heap up; to stack up; to repeat many times over; to go through repeatedly; to accumulate
to shine; to glitter; to sparkle
colour; color; complexion; skin colour; look (on one's face); expression; appearance
restoration; return; reduction; resolution; deoxidization
gradually; steadily; slowly; little by little; step by step; by degrees
collapse; crumbling; breaking down; (radioactive) decay; disintegration
to begin; to start; to happen (again); to begin (anew); to date (from); to originate (in)
before long; soon; almost; nearly; finally; in the end
judgment; judgement; decision; verdict
intention; wish; purpose; mind (to do)
which way; which direction; which one (esp. of two alternatives); who
one side; one party; counterpart; one of a pair; fellow; mate
given that ... it is only natural that ...; ... being the case, it is unavoidable that ...; (precisely) because ...; contrary to expectations ...
child; kid; (one's) child; offspring; young (animal); young woman; offshoot
to shed light; to cast light
to notice; to recognize; to recognise; to become aware of; to perceive; to realize
to advance; to go forward; to precede; to go ahead (of); to make progress; to improve; to deepen
distinction; differentiation; classification
to go to ruin; to go under; to fall; to be destroyed; to die out; to become extinct
to wait; to await; to look forward to; to depend on; to need
instant; moment; for an instant
(theatrical) blackout; taking a (sudden) turn for the worse; rapid deterioration
certain; sure; definite; reliable; sound; solid
to get used to; to grow accustomed to; to become skilled in; to become experienced at; to become tame; to become domesticated
correspondence (to); equivalence; suitability; coordination; dealing with; coping with
dark; gloomy; depressed; dispirited; dark (in colour); dull; ill-boding
least; lowest; worst; awful; horrible; at the very least
avenue; street; coming and going; street traffic; flow (of water, air, etc.); transmission (of sound); reach (e.g. of voice)