 Structural ambiguity occurs when constituents can relate to each other in different ways, resulting in different meanings, even though none of the individual items may be ambiguous. For example, this complex nominal compound can be interpreted in two ways, depending on its structural hierarchy. A container for porcelain eggs and an egg container made of porcelain. In phrases and sentences there are three central triggers for structural ambiguity in present-day English. Coordination, prepositional phrases or more generally adverbials and non-finite clauses. For example, the coordinate structure in the noun phrase old men and women has two interpretations, old men and women of any age and men and women who are both old. Or take the sentence John saw a robot represented in a shorthand version of X bar syntax. If we add an adverbial, for example the prepositional phrase on the way to work, we have two different structural options of prepositional phrase attachment. One where the robot is in fact going to work and one where John saw the robot while he was on his way to work. In non-finite clauses such as the chickens are ready to eat, either the chickens are ready to eat something or they are ready to be eaten. Or look at this construction where the meaning depends on the analysis of is as a lexical verb or as an auxiliary verb.