How not to get all mixed up about "mixed" conditionals

Traditional textbooks describing English grammar (e.g. Onions 1904; Eckersley and Eckersley 1960; Thomson and Martinet 1982; Graver 1979; Murphy 1994) concentrate generally on three main types of conditional sentences based on verb forms used in order to mark time reference and to stress the reality versus the unreality relation in conditionals. They are classified as open (a condition capable of being fulfilled; future time reference), hypothetical (contrary to the assumption or expectation; present or future time reference) and unreal (contrary to the fact; past time reference).