The authors wish you to read it with a pencil in your hand, for you will often be asked to make certain notations, to write answers to particular questions.
作者们希望你在读这本书的时候手里要拿上一支铅笔，因为我们要求你经常做点笔记，或是将一些具体问题的答案写下来。
A notation, usually a question mark, calling attention to an item in order to question its validity or accuracy.
疑问号一个记号，通常为问号，以引起对某一事物的注意以便就其有效性或准确性提出质疑
