说明：  正演模拟中交错网格是比较准确的正演模拟方法，本程序介绍交错网格正演程序的关键问题，便于初学者学习。希望对你们有帮助
(Staggered forward modeling is more accurate forward modeling method, the program introduces key issues staggered forward procedure, easy for beginners to learn. I hope for your help)