unique; matchless; unparalleled; unparallelled; never again
fluently; without hesitation; without faltering
optical device; optical element
light emitter (fiber optics)
e-signature; electronic signature
electrodynamics; electromagnetism
amusement program; amusement programme
external unit; external device
hard to control; unmanageable
civilian control (of the military)
somehow or other; for some reason or another
to be caught by the enemy
stupid; meaningless; worthless; hopeless (person, situation); beyond help; beyond saving
not long has passed since ...
electronic; electronic formula
double-glazed window; double window; storm window