From the functional point of view, a Chinese sentence is usually composed of topic and comment. The former, placed in the initial position and definite in reference, serves to set up a starting point or to initiate a discourse; the latter, the rest of the sentence as a whole, proceeds to give “new” information about the former. This feature predominantly manifests itself in three types of sentences typical of the Chinese language, namely, 1) Nominal Predicate Construction; 2) S-P predicate Construction; 3) Existential Construction.
 Loar, J. K. (2011). Chinese syntactic grammar: functional and conceptual principles. New York: Peter Lang.