Abstract. The requirements for a system are often specified as textual use cases.
Although they are written in natural language, the simple and uniform sentence structure used makes automated processing of use cases feasible. However, the numerous use case approaches vary in the permitted complexity and variations of sentence structure.
Frequently, use cases are written in the form of compound sentences describing several actions. While there are methods for analyzing use cases following the very simple SVDPI (subject - verb - direct object ... indirect object) pattern, methods for more complex sentences are still needed.
We propose a new method for processing textual requirements based on the scheme earlier described in [13]. The new method allows to process the commonly used complex sentence structures, obtaining more descriptive behavior specifications, which may be used to verify and validate requirements and to derive the initial design of the system.