请教一下SAT试卷说明里两句话的意思?数学：
数学： Unless otherwise specified, the domain of any function f is assumed to be the set of all real numbers x for which f(x) is a real number.
阅读（一篇文章对应两个题目）：Answer the questions on the basis of what is stated or implied in each passage and in any introductory material that may be provided. (其中的introductory material ,在文章中并没有,是不是说文章本身就是开头的部分就是这个introd...)