There is much literature about the licensing of complement clauses by complement-taking predicates. However, less has been written about the licensing of adverbs in a complement clause. This article addresses the licensing of English evidential adverbs in complement clauses extracted from the NOW corpus. The article discusses three factors that determine the distribution of evidential adverbs in complement clauses. These are the nature of the evidential adverbs, the constraints of the complement clause and the anchor of the evidential adverb. To explore the role of these three factors, I adopt the hierarchical scopal theory of Functional Discourse Grammar (FDG). If a complement clause licenses the inclusion of the evidential adverb, then there is a match. Should there be no alignment between the complement clause and the adverb, there will be a mismatch. The results of the analysis of the data show that there are mostly matches, which occur with either a current speaker anchor or an actor anchor. Secondly, it appears that in cases of mismatches, there is always a current speaker. It thus appears that a current speaker anchor can override the constraints of the complement clause.