This paper tries, from the perspective of diachrony and synchrony, to analyze the grammaticalization features and cognitive motivations. The grammaticalization has led to a set of corresponding changes in compound or complex structures. The motivations are analogy and reanalysis. The increased richness of connectives is out of its pragmatic need: the linguistic structures get more and more tight as man's thinking logic becomes more and more compact so that more and more function words are needed to represent various structures and ...
