smooth (of a surface); glassy; smooth (of an action, proceedings, etc.); fluent (speech); continuously differentiable
letter (of an alphabet); character; writing
fingertip; finger; toe tip; toe
nerve; nerves; sensitivity
to stroke; to caress; to brush gently; to comb (hair); to smooth down
(and) then; and; thereupon; in that case; then; so
unevenness; bumpiness; roughness; imbalance; inequality; unevenness
friction; rubbing; chafing; discord; friction
to slide; to glide; to slip; to skid; to be slippery; to fail (an examination); to lose (a position)
here and there; in places
to expose (to the sun, public, danger, etc.); to bleach; to refine; to rinse (vegetables); to soak; to doxx
beginning; start; outset; at first; at the beginning; initially
wound; injury; chip; crack; flaw; defect
conclusion (of an argument, discussion, study, etc.); conclusion
breathing; respiration; knack; trick; harmony; balance
pulse; vein; chain (of mountains, etc.); hope; thread (of an argument)
rest; break; recess; intermission
as (much) as possible; as (much) as one can; wherever practicable; if possible
firing one shot at a time; single-shot gun; having only one engine; single-engined aeroplane; one-shot (e.g. story); non-serial
propeller-driven aircraft; prop plane
last century; previous century; ancient times; old times
this way (of doing); this method; this sort (of thing); this type
to be taken for granted; to be generally accepted; to be the established wisdom; to be the (social) convention; to be the customary thing to do
(the) mainstream; main course (of a river); main stream
to account for; to make up; to occupy (a place, position, etc.); to hold (a rank, seat, etc.); to occupy (one's mind, heart, etc.); to weigh (on one's mind)
power; motive power; three-phase electricity
sky; the skies; high-altitude sky; upper air
to come near (to); to approach; to be on the verge of; to be about to reach (a stage, period, etc.); to overhang; to hang over
appeal; call for something; request; axiom
inside a plane; in-flight
to be based (on); to be founded (on); to be grounded (on); to be due to; to come (from); to arise (from)
presumption; assumption; estimation
to compare with the eye; to judge by comparison; to take into consideration; to bear in mind
revolution; rotation; turning; turning (an aircraft or ship)
to listen repeatedly; to listen again; to ask a question in return; to ask again; to ask for a repeated explanation
easily; readily; quickly; lightly (seasoned food, applied make-up, etc.); plainly; simply
to withdraw; to leave; to retire; to back down; to give up
to some extent; to a certain extent
supply; provision; raising; procurement
association; socializing; socialising; fellowship