【单选题】passage three:questions 21~25 are based on the following passage. Sign has become a scientific hot button. Only in the past 20 years have specialists in language study realized that signed languages a...
A.
a new way to look at the learning of language
B.
a challenge to traditional, views on the nature of language
C.
an approach: to simplifying the grammatical structure of a language
D.
an attempt to clarify misunderstanding about the origin of language