摘 要： 　　Abstract 　　黄自是我国非常重要的音乐家和教育家。 　　Huang Zi is one of the most important musicians and educationalists in China. 　　随着现代社会对声乐演唱者及声乐作品演绎要求的日益提高，必须从作品的内容，情感，思想，演唱方法及演绎技巧等方面进行分析和研究。 　　Resulting from the increasingly improvement in require of vocal music in modern society, in terms of expressiveness of works and art of singing, the analysis of a vocal work should involve such respects as contents, emotion, thoughts, singing methods, and performing skills. 　　本文介绍了黄自的生平简介以及他的三首艺术歌曲：《春思曲》《思乡》《玫瑰三愿》的基本内容及情感表达，结合当时的时代背景，总结出这三首艺术歌曲的音乐影响和时代意义。 　　This text briefly introduces the life of Mr. Huang as well as somes of his works, namely A,B, and C. Furthermore, it explains the basic components and emotional expression according to the historical background, and concludes the Influences on later music and significances of the age. 　　再从切身的演唱过程中，找出这三首歌曲的演唱方法及演绎技巧。从而更好的诠释出这些作品。 　　With experience of practice and from those conclusions, singers might get inspirations of expressing leading to an intire interpretation. 　　A春思曲Spring Moaning 　　B思乡Homesick 　　C玫瑰三愿Three Wishes of a Rose 　　文中ABC代表这三首歌名，应该是这样写的吧。但不确定你们是怎么教的，所以单独注一下以方便你修改替换。

Aim: To isolate high activity saccharifying enzyme. Methods: The spore suspension were alternately performed by UV and photoreactivation, and the high-producing strain was primary screened by the mothod of transparent circle on plate. The secondary screening was carried out by the flask culturation. Conclusion: A strain 12 was obtained by UV mutagenesis. Using flask culturation, the enzyme activity was 5544.3 U/mL, which was 25.41% higher than of control strain, and the effect was significant. The mutanted strain identified by the test of genetic stability showed favorable stability. Key words: UV mutagenesis, Saccharifying enzyme, Aspergillus niger, Strain breeding 哈哈，你倒是挺会偷懒的，祝你答辩顺利！