Then it points out that X bar theory has some serious defects which determine that the X Bar theory and its derivation Head theory shouldn t be used to analyze the syntactic structural system of modern Chinese.

An X-bar theory approach to the DP hypothesis;

This paper analyzes English ambiguity with X-bar theory in terms of transformational Grammar(TG),the research accounts for the cause of ambiguity,thus supplying a new perspective for disambiguation.

Based on the universality of human languages as the prerequisite,the author proposes that "NP-de-VP" phrases in Chinese are similar to the v-ing-phrases in English and uses Chomsky s X-bar theory and the thematic theory to reveal their inner structures.

X-factor theory for solving the problem was introduced,it is used in semiconductor factory gradually now.

This study aims to analyze the process of compensatory lengthening(CL) in language by means of the three theories of the timing units—the CV theory,the X theory and the moraic theory,and attempts to illustrate that non-linear theories can handle satisfactorily the resyllabification triggered by compensatory lengthening.