The research investigated the time course of integrative semantic processing during sentence processing. Reading time was measured on sentences containing an NP composed of an adjective and a noun whose combined meaning was plausible or anomalous (Experiment 1) or was typical or atypical (Experiment 2). The noun in the NP was either plural or singular. Plural nouns were expected to be more rapidly integrated with a preceding adjective than singular nouns because plural nouns can be ruled out as the first noun in a noun compound more rapidly than singular nouns. The results confirmed this prediction, showing that the effects of semantic plausibility and typicality were observed immediately during the processing of plural nouns, but were observed at a delay following the processing of singular nouns. Implications for theories of sentence processing are discussed.