Abstract. This article sets out some of the results of wider research on the linguistic databases of a natural language generation system. One of the necessary steps in the building of such databases is to determine the linguistic means the generator must have in order to produce a linguistic form that corresponds to the semantic representation given as an input. We wish to focus here on the theoretical choices and issues rather than on the application itself. We assume that texts have a syntactic structure, whose characteristics are partly comparable to the syntactic structure of a sentence, and that a connective can be considered as a textual predicate which has arguments that are constrained in the same way as the arguments of a verb. This article will concentrate more specifically on one particular semantic relation — the simultaneity of two events — and will show how the taxonomy of the associated connectives can be elaborated. Finally, we will set out some of the major developments of this research, which concern the interface between conceptual and linguistic knowledge.