下一楼›：里面包含三部分，现打包成一个文件，包含了各种各样的速算方法，秘诀。看了就知道。
绝对支 ..(巨无灞)
‹上一楼：顶呀
hanks a lot. I think it's one of ways for learning in short time :-)(巨无灞)