Although every aspect of language is complex, children before th

Although every aspect of language is complex, children before the age of ______ already know most of the intricate grammaticalsystem of their native language.
A、three
B、four
C、five
D、six
【正确答案】：C
【题目解析】：Although every aspect of language is complex, children before the age of five already know most of the intricate grammatical system of their native language.