Recent work in generalized quantifier theory has greatly increased our understanding of the types of quantification expressible in natural language. Keenan and Moss (1985) prove an expressive completeness result concerning standard unary quantifiers in English. Since Barwise (1979) proposed a semantics for "branching quantifiers, " various linguistic expressions for binary (generally, polyadic) quantifiers have been observed and discussed in the frame of generalized quantifier theory (Keenan 1987, 1992; van Benthem 1989, among others). Here we prove English has the full expressive power for binary quantifiers, which is revealed by gapping constructions. For the last decade or so, generalized quantifier theory has been developed to...