Classifier constructions in English such as three glasses of water are ambiguous between an individuating reading, in which the DP denotes plural objects consisting of three individual glasses of water, and a measure reading, in which the DP denotes quantities of water which equal the quantity contained in three glasses. A plausible semantic account of the contrast has been given in Landman 2004. In this account, on the individuating reading, the nominal glasses is the head of the noun phrase and has its expected semantic interpretation, while in the measure reading, three glasses is a modifier expression modifying the nominal head of the phrase water. However, there is little direct syntactic evidence for these constructions in English. Modern Hebrew, however, provides support for Landman's analysis of the dual function of classifier heads. There are two ways to express three glasses of water in Modern Hebrew. The first is via the free genitive construction where a nominal head in absolute form takes a prepositional phrase complement as in šaloš kosot šel mayim, and the second using the construct state as in šaloš kosot mayim. The first has only the individuating reading, while the second is ambiguous between the individuating and measure readings. We show that only in the construct state are the syntactic conditions fulfilled which allow the classifier + numeral to be interpreted as a (complex) modifier of the syntactically embedded noun.