8. The method of text script generation for a corpus-based text-to-speech system according to claim 1 , said method presents at least unit-type covering rate and unit-type hit rate as a first performance index and a second performance index respectively, for the text script generation in the corpus-based text-to-speech system.
8. The method of text script generation for a corpus-based text-to-speech system according to claim 1 , said method presents at least unit-type covering rate and unit-type hit rate as a first performance index and a second performance index respectively, for the text script generation in the corpus-based text-to-speech system. 9. The method of text script generation for a corpus-based text-to-speech system according to claim 8 , wherein said unit-type covering rate is defined as r C =  U S   U  , U is the set of unit types covered by the set of all unit instances in said source corpus, and U S : is the set of unit types covered by the set of all unit instances in the selected text script.