Languages in the world can be classified into families, such as the Indo-European family the Sino-Tibetan family, the Afroasiatic family, the Austronesian family, the Austro-Tai Family, and the Altaic family. Among them, ______ is the first and most

Languages in the world can be classified into families, such as the Indo-European family the Sino-Tibetan family, the Afroasiatic family, the Austronesian family, the Austro-Tai Family, and the Altaic family. Among them, ______ is the first and most widely investigated language family of the world. ()

A.Sino-Tibetan

B.Afroasiatic

C.Austronesian

D.Indo-European

正确答案是D