The aim of this paper is to examine an ambiguity of Chinese wh-adverbs:zenme 'how' is sometimes construed as causal rather than method or manner, as in?' We show that causal zenme typically appears before modals, behaving very much like a matrix predicate. By contrast, its postmodal counterparts are interpreted as method or manner preverbally, and as result postverbally. From the viewpoint of ontology, the structural distrbution of zenme (yang) embodies a "cause-effect" relation, and in-between, we have agent-sensitive concepts such as method and manner. In terms of the syntax-semantics interface, it is demonstrated that the various interpretations of zenme (yang) are conditioned by the syntacits projections it occurs in. Namely, premodal zenme takes the whole sentence as its complement, which corresponds to an event. This results in the causal reading Postverbal zenmeyang, on the other hand, serves as a complement to VP, corresponding to a resultant state. Hence the resultative reading. Furthermore, when method/manner zenme (yang) serves as a VP-adverbial, it modifies an action, thus sensitive to subject agentivity. Finally, we find that causal zenme actually patterns with weishenme 'why' with respect to their syntactic behavior, which can be accounted for by adopting the notion of unselective binding and relativized minimality.