http://cyc7.cycnet.com/xuezhu/image/hjA0031.jpg这个网站可以告诉你答案!!
http://www.scol.com.cn/nsichuan/bsxw/20050323/200532395042.htm(这个是图)http://china.qianlong.com/4352/2003/11/13/1040@1707617.htm(图,大一点)http://www.xxjxw.com/Photo/jxsc/200412/1.html(图,更大)你自己去写吧,对照着图,我地理不好的~~