单项选择题

Science textbooks and technical and professional journals are usually made up of several parts and contain various special features, many of which have a standard format. (31) usually contain a large number of these parts; journals and (32) contain many, but not all of them.
Knowing where to look for information and (33) to expect in a book can greatly increase your ability to use all the information there. Explanations of and practice using some of these textbook parts and (34) are covered in these even numbered lessons. The features in textbooks are (35) into the following three categories. Front matter is the (36) -numeral paginated section at the front of most books. The text is the main body of the book. The (37) matter comprises the additional sections at the back of most books. (38) our discussion of these three sections will deal mainly with textbooks, the practice provided will greatly (39) your comprehension of scientific (40) as well.