完全性 
参考定義
IEEE std 830-1998 (Complete)
An SRS is complete if, and only if, it includes the following elements:
a) All significant requirements, whether relating to functionality, performance, design constraints,
attributes, or external interfaces. In particular any external requirements imposed by a system specification should be acknowledged and treated.
b) Definition of the responses of the software to all realizable classes of input data in all realizable classes of situations. Note that it is important to specify the responses to both valid and invalid input values.
c) Full labels and references to all figures, tables, and diagrams in the SRS and definition of all terms and units of measure.
Use of TBDs
Any SRS that uses the phrase "to be determined" (TBD) is not a complete SRS. The TBD is, however, occasionally necessary and should be accompanied by
a) A description of the conditions causing the TBD (e.g., why an answer is not known) so that the situation can be resolved;
b) A description of what must be done to eliminate the TBD, who is responsible for its elimination, and by when it must be eliminated.
