With the increasing complexity of real-time control systems, it is important to have sufficient predictability support for a development approach in order to promote the likelihood evelopment success. To achieve this, the abstraction/refinement activities during the development should be performed in an efficient way. In this paper, we first briefly introduce the role of the semantics of languages in system development. Then we investigated how the semantics of development languages can support efficient abstraction/refinement. Subsequently, the insufficient predictability support of existing design approaches for real-time control systems are illustrated by an example. Finally, a predictable development approach for real-time control systems is introduced to overcome this problem.