第6题: [名词解释]productivity (as a property of language) 参考答案:
By productivity, language is designed to make its users form and understand an infinite sentences, most of which are never before produced or heard. For instance, we can write a sentence like the following and go on endlessly: "He bought a book which was written by a teacher who taught in a school which was known for its graduates who...".
答案解析:
[解析] 本题考查语言的定义特点之一——多产性，考生也应掌握语言的任意性、二层性和移位性。
第21题: [单项选择]设f(x)连续，[*]，则下列结论正确的是( ) A. f(1)是f(x)的极大值 B. f(1)是f(x)的极小值 C. (1，f(1))不是曲线y=f(x)的拐点 D. f(1)不是f(x)的极值，但(1，f(1))是曲线y=f(x)的拐点 参考答案:B 答案解析:[详解] 因为[*]，所以由极限的保号性，存在δ＞0，当0＜|x-1|＜δ时，有[*]，即当x∈(1-δ,1)时，f'(x)＜0；当x∈(1,1+δ)时，f'(x)＞0。根据极值的定义，f(1)为f(
