带有后退和前进选项的PHP测验

I want a PHP Quiz script which will having following features

1. User can select answer from multiple choices (radio button or checkboxes ) along with a small textarea for brief explanation where needed.
2. User can go back and forth to change any answer
3. Time will be on whole quiz not per question level
4. General Admin work of a quiz

I have searched but did not found a good solution for my need. Have anyone come across a matching PHP opensource script?

I haven't seen anything specifically like that, but you can adapt from survey, voting, or ranking scripts. Why not just write it yourself? seems like a pretty simple script to write up.

For example : http://sourceforge.net/projects/uccass/