uncharted territory; unknown waters; unfamiliar terrain
it is assuredly (that)...; can say with confidence that it is...
nest; rookery; den; haunt; (spider's) web
exceedingly; extremely; decisively
concentration; thickness; density; cardinality
to keep; to preserve; to hold; to last; to endure; to keep well (food)
difficult; hard; impossible; unfeasible; fussy; particular; gloomy
therefore; for that reason; such being the case
substantial; real (as opposed to nominal)
experienced; already had an experience (with something)
to concern; to be related
to defend against; to protect against; to prevent; to avert; to avoid
management; administration; operation
estimate (of costs); budget
maintenance; preservation; improvement
sleek; smooth; thin (of a liquid); without hesitation or delay
this is why; this means; it is the case that
naturally; of course; understandably
considerably; not a little; in no small numbers
to affect; to impact; to influence
careless; stupid; thoughtless; heedless; unobservant; inadvertent
to approach; to draw near
recommendation; endorsement
grateful; thankful; welcome; appreciated; evoking gratitude
to be greatly obliged; to be very sorry
surface of the earth; ground surface
area; domain; territory; field; range; region
comparatively; relatively
study; research; investigation
permanent stationing; staying permanently; resident (program, file, etc.)
sorcery; black magic; netherworld; world outside the six realms where evil spirits roam
technology; engineering; technique; skill; art; craft
weather measurement station
little more than; only slightly better than; almost the same as
observation; survey; measurement; opinion; prediction; thinking
base (military, expedition, etc.)
defense; defence; guard; policing; security
shelter; safe shelter; evacuation shelter; place of refuge
first; foremost; most important; best; greatest; above all
difference; distinction; discrepancy; mistake; error