请教一下SAT试卷说明里两句话的意思?数学：
问题描述：
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...)
答
"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" means that the number of every question is based on real number (R).
"in any introductory material that may be provided" refers to any material addition to the reading packet.