on and after; as from; hereafter; thereafter; since
atomic physics; nuclear physics
major subject; special study
iron (Fe); strong and hard (as iron); railway; railway enthusiast
union; coalescence; amalgamation; copulation; penetration
collapse; crumbling; breaking down; (radioactive) decay; disintegration
transuranium element; transuranic element; super heavy element
instability; insecurity; crankiness
main question; real issue at hand
abbreviation; omission; outline; gist; plan; strategy
leaving as is; leaving alone; leaving to chance; neglecting; abandoning
criticism; blame; censure; attack; reproach
repeatedly; frequently; over and over; exceedingly; sincerely; very much
three times; thrice; many times; over and over again; often
to sound; to ring; to resound; to echo; to roar; to rumble
number; edition; sobriquet; pen-name; size (of printing types, canvases, knitting needles, etc.); suffix attached to names of ships, trains, airplanes, etc.
observation; survey; measurement; opinion; prediction; thinking
operating together; working together; being linked (to); being tied (to); being connected (with); interlocking
health; healthy; sound; fit
highly conscious; highly aware; well-versed; highly knowledgable
10^8; 100,000,000; hundred million
making a round trip; going and returning; round-trip ticket; return ticket; correspondence; exchanging (letters)
model; pattern; paragon; exemplar
unity; consolidation; uniformity; unification; compatible
at the most; at best; to the utmost; as much as possible; as much as one can
food; foodstuff; eating; appetite; meal; portion
to abate; to decrease; to diminish; to shorten
contriving (to raise funds, to find time, etc.); working out (a solution)
amount of money; sum of money
incremental; step-by-step; gradual; stepwise
part; portion; amount; worth (as in "two days' worth"); one's means; one's place; one's duty
profound; deep; unfathomable