有道题求助各位大牛

费豆豆700

The mistakes children make in learning tospeak tell linguists more about how they learn language than the correctforms they use.

(A) how they learnlanguage than

(B) how one learnslanguage than

(C) how childrenlearn language than do

(D) learninglanguage than（C）

(E) their languagelearning than do

答案看不明白，难道不是than前面用how引导的从句后面也要平行吗？