It is mentioned in the last paragraph that Dr. Pet...

Câu hỏi: It is mentioned in the last paragraph that Dr. Petitto plans to study __________.

A what happens when babies have the opportunity to learn both speech and sign language           

B whether all children speak and make motions with their hands at the same time

C the assumption that the human brain prefers sign language to speech 

D whether the sign system of the deaf is the physical equivalent of speech