In this paper, we discuss the conditions and limitations of the co-occurrence of adverbs and the sentence final `le` in modern Chinese. We first sort out the grammatical nature of sentence-final `le`, and then describe the phenomenon of co-occurrence of adverbs and `le`. Through this analysis, we find that those adverbs that can be used to describe a change in situation can appear together with `le`, whereas those that can only be used to describe the current state of things or situation cannot appear together with `le`. However, even if there is a change of situation, `le` needs to be omitted when the direction of the change is different from the expected direction of the speaker that is revealed by the adverb. Therefore, the co-occurrence of adverbs and `le` is not only related to changes of situation, but is also restricted by the cognitive expectations of the speakers.