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(Redirected from shouldn’t)
Although shouldn't is derived from should not, the two are not grammatically interchangeable. While "Shouldn't I do it?" is grammatical, "Should not I do it?" is no longer acceptable. It would instead be "Should I not do it?"
1983, Zwicky, Arnold M.; Geofrey K. Pullum, “Cliticization vs. Inlection: English n't”, Language, volume 59, number 3, pages pp. 502–513: