I don't clearly understand the differences between through and throughout.
Can you explain to me the differences?
In the below question, (D) is an right answer. (C) can be an answer, too?
We did develop a plan with goals laid out _______ the next three years as to what we need to accomplish and when to succeed in the end.
D is better, as it emphasizes the steadiness and continuity of the process; but C is possible.
Generally, "throughout" can be used only of periods (whereas "through" can be used inother contexts: 'he succeeded through sheer hard work', 'he spoke through an interpreter'. 'he blew into the trumpet through the mouthpiece'... etc.) And in expressions of periods, 'throughout' can be more accurately replaced by 'all through':
It was the same throughout his life.
It was the same all through his life.
It was the same through his life.