OG详解-OG2 文法 Q26

Choice D is the best answer. “In addition” logically signals that the information in this sentence—that the Twentieth Amendment requires newly elected US senators and representatives to be sworn in on January 3 —is separate from and additional to the amendment’s mandate concerning presidential inaugurations. 
Choice A is incorrect because “instead” illogically signals that the information in the sentence presents an alternative to or substitute for the Twentieth Amendment’s mandate concerning presidential inaugurations. Rather, the sentence presents a separate requirement in addition to that one. Choice B is incorrect because “for instance” illogically signals that the information in the sentence exemplifies the Twentieth Amendment’s mandate concerning presidential inaugurations. Instead, the sentence presents a separate requirement in addition to that one. Choice C is incorrect because “specifically” illogically signals that the sentence provides specific, precise details elaborating on the Twentieth Amendment’s mandate concerning presidential inaugurations. Instead, the sentence presents a separate requirement in addition to that one.