Are both expressions "At the beginning" "In the beginning" valid and equivalent? The first "seems wrong" to me, but it has more Google results.
word choice - "At the beginning" or "in the beginning"? - English ...
The beginning of the century is a period of time which is short compared to the century but rather long otherwise; Some people may use this phrase to mean the first decade or even longer.
"At the beginning of the century" or "in the beginning of the century"?
grammaticality - "Upon" at the very beginning of a sentence - English ...
Can one use "Yet" at the beginning of a sentence as follows? Yet, he came late. Is this grammatical?
grammaticality - "Yet" at the beginning of a sentence - English ...
The "approximately" at the beginning of the list refers to each of the percentages, which have been rounded to a lower precision. I am wondering if the following comma is appropriate here, or generally when one is trying to apply a modifier list of figures.
The sentence where you used though at the beginning, seems incomplete. All you can do is, combine the last two sentences by removing the full-stop and starting though with a small t.
For example, the beginning of a race track is called the starting line and the end is called the finish line. There are of course more nuances involved than I gave in my answer, but the question was about the words in general, not in any particular shade of meaning.