题目内容：
Documentation of a software package is normally produced for two purposes．One is to explain the ____(71)______ of the software and describe how to use them．This is known as_____(72)_____ because it is designed to be read by the user of the software．The other purpose of documentation is to describe the software’S internal composition SO that the system can be maintained later in its life cycle．Documentation of this type is known as_____(73)_____ ．
第71题答案__________
．
A．
plans B． cost
C． features
D． schedules
参考答案：
答案解析：