提取Operon的前序序列。在生物信息领域，处理微生物信息时，经常会要提取其操纵子的前序序列。由于操纵子的命名诡异，所以提取时经常较为困难。本程序以大肠杆菌为模式生物完成了此操作-Extract the pre-sequence of operons. In the field of bioinformatics, when processing with microbes, we often need to draw the pre-sequence of their operons. Due to the wierd naming method of operons, the work can be really tired. This program fullfill the work of E.coli.