Hi soohyun1110.
For what you want to do, the best option might be to use a Custom item. Basically, you would have to use HTML code to create the fill in the blank item. MediaLab comes with sample code that you can try out and modify; take a look at the Custom Items section of the MediaLab manual for more information and where to find the examples in the Samples folder that came with the installation of MediaLab: http://www.empirisoft.com/medialab/h...stom_items.htm.
The tricky part would be that you would have to modify the existing HTML code in some way to record whatever participants type in the box and then automatically move on to the next item. I don't have any suggestions about how to accomplish this off the top of my head, but if you think that the Custom Item option is one you wish to explore, I'd be happy to help you to the best of my abilities.
Jason Reed
Empirisoft Software Support Specialist