bertahun-tahun definition
bertahun-tahun means beberapa tahun lamanya. So in that sentence there is an adverb of time. In this sentence the indication of time plays an important role because it explains how long the conquest has been carried out by Thanos. while in TL the non-professional translator uses the word "sepanjang" to describe the adverb of time. While the word "sepanjang" does not specify how long it took. Therefore the error that occurred in this datum deals with completeness.