ABSTRACT
WCs can be used in many different ways. They may have several meanings or connotations and fulfil various syntactic functions. In this chapter I will review the various types of (finite) WC.1 As I have already said, this typology is relevant to the use of the tenses, for different types may sometimes require different tense forms. To illustrate this point, I will draw attention to the use of tenses in the various types of WC when they depend on an HC (head clause) referring to the future. As is well known, adverbial WCs cannot normally use the future tense or the future perfect if the situation (i.e. action, event, state, etc.) referred to in the HC is represented as posterior to the moment of speech: they use the present tense and the present perfect instead. Similarly, adverbial WCs do not use forms with would or would have if they depend on an HC whose situation is represented as posterior to a past time of reference: they use the preterite and the past perfect instead. For example:
(1)
(a) I will leave when they {arrive/*will arrive}. (b) I will leave when they {have arrived/*will have arrived}. (c) I promised I would leave when they {arrived/*would arrive}. (d) I promised I would leave when they {had arrived/*would have arrived}.
