The cleft is a focus construction and it has been much discussed in many frameworks. In particular, what can be clefted is a intriguing subject.
This presentation focuses on and considers the cleftability of adverbs. There are two points to be emphasized here: The first is that with data expanded, there actually exist data of clefted adverbs, as opposed to the proposal of some linguists such as Emonds that only NPs and PPs can be clefted. And whether or not they are possible is attributable to dialectal or idiolectal differences. The second is that the further examination of clefted adverbs reveals that not all adverbs belonging to the category but only VP-internal ones can be clefted. This fact is confirmed by syntactic tests that guarantee the VP-internal status of adverbs. Moreover, the VP-internalhood can be extended to what is traditionally called 'adverbial clauses.'