Extraction.  These are phenomena which generative grammar refers to as ‘overt displacement’, as we find it in wh ‘movement’ constructions.  Compare the wh phrases ‘what — annoys Mary’ versus ‘what Mary put — there’, as they would occur in a context ‘I know what annoys Mary’ or ‘I know what Mary put there’.  The dash marks the spot where a noun phrase would fit in a normal declarative sentence: ‘this record annoys Mary’, ‘Mary put the record there’.  Assigning the type wh/(np\s) to ‘what’, we can derive wh for the first example, with a np hypothesis in the left-peripheral subject position.  If this hypothesis (the ‘gap’) occurs internally, as in the second example, it is unreachable for (N)L: one cannot derive np\s for ‘Mary — put there’ (nor s/np, for that matter, which would require a right-peripheral gap).