In this paper, the technology of ultrasonic extraction of flavonoids from grapefruit seed was studied. The orthogonal design method was used to optimize the process. The results showed that the optimum extraction parameters were ultrasonic ratio 1:50 (g / mL) , Ultrasonic power of 280w, extraction temperature 65 ℃, extraction time 30min. Under these conditions, the extraction rate of flavonoids from grapefruit seed was 3.380mg / g. Ultrasonic enhanced extraction has the advantages of low temperature, high extraction efficiency and low cost, which can provide reference for industrial application.

Dialogue theory provides a new perspective on interpreting the dialogue in cultural context and communication mode in translation. Based on Bakhtin 's theory of dialogue and Robinson' s translation rhetoric and translation ethical dialogue model, this paper examines the problem how to achieve harmonious dialogue between all the parties involved in the translation of Chinese classic poem. By employing methods of exemplifications and comparison, the study made an interpretative analysis of the corpus from "A Tribute to King Teng's Tower ". It found that dialogue theory helps to avoid translation defaults such as misinterpreting and improper omission in conveying the original author's creative intention in the translation of Chinese classic poem. It suggests that dialogue model exerts certain implication on interpretation and inspiration in the translation of Chinese culture classics.

English teaching materials compilation has been developed rapidly at present China, yet the evaluation of teaching materials lags far behind. In combining rational aspects of theories and practices about teaching materials evaluation both at home and abroad with the features of English Audiovisual and Speaking course, this paper attempts to construct an evaluative framework on English Audiovisual and Speaking Teaching Material from three perspectives: macro evaluation, microevaluation, and users' evaluation. Followed by a detailed analysis of the criteria in applying this framework, it hopes that the ideas presented in this paper may trigger more focused researches on the evaluation of English Audiovisual and Speaking teaching materials.