I have asked you a question yesterday...
http://hk.knowledge.yahoo.com/question/question?qid=7012110300608
I get a similar question...
http://www.flickr.com/photos/85983799@N04/8150593132/
Please see part (c)
If I follow your method in the previous question
My answer
http://www.flickr.com/photos/85983799@N04/8153521321/in/photostream
But the suggested solution....
http://www.flickr.com/photos/85983799@N04/8153509607/in/photostream
Can you help me to explain this???
Thankyou!!!!!