第5题: [单项选择]Stokoe' s argument is based on his belief that______ A. sign language is as efficient as any other language B. sign language is derived from natural language C. language is a system of meaningful codes D. language is a product of the brain 参考答案:D 答案解析:根据最后一段中的Stokoe所言"What I said...is that language is not mouth stuff--it’s brain stuff.”,便可肯定[D]为正确答案。