The choice relation framework (CHOC'LATE) provides a systematic skeleton for constructing test cases from specifications. An early stage of the framework is to identify a set of categories and choices from the specification, which is not a trivial task when this document is largely informal and complex. Despite the difficulty, the identification task is very important because the quality of the identified categories and choices will affect the comprehensiveness of the test cases and, hence, the chance of revealing software faults. This paper alleviates the problem by introducing a technique for identifying categories and choices from the activity diagrams in the specification. This technique also helps determine the relations between some pair of choices in the choice relation table - an essential step of CHOC'LATE for the subsequent generation of test cases.