19.______dog was the first animal to be domesticated is generally agreed upon byauthorities in the f

题目

19.______dog was the first animal to be domesticated is generally agreed upon byauthorities in the field.
A)until the
B)it was the
C)the
D)that the
请问答案为什么选择D,请帮我详细的解答,谢谢~

答案

这个表示：狗狗是第一种被驯养的动物
a until 表示 直到……这里不符合句意
b it was the 这个句子已经倒装,后面有谓语动词was所以前面不需要了
c the 单用the缺少成分
所以选择D That在这里指代这个事情