Va~rious devices for the imp rovement of phrase structure grammars (PSG) have been suggested recently. In particular, the PSG model with a pushdown store (PSG/PDS) a s described by VoYngve, and the PSG with subscripts (PSG/S) as described by G oHarman are considered. It is contended that such devices, even if they may do away with some of the difficul_ ties of PSG, do not contain sufficient gene_ rative power to produce the structurally corn_ plicated sentences that are generated by other gramma rs (e.g. , of transformational type). The handling of multiple disco,Ltinuous con_ stituents (DC) in PSG/PDS, as well as the use of :leletion rules in PSC./S is examined and criticized. It is shown that the improvements on PSG will not allow the grammar to generate a ii the sentences of the languag...

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