first of all I wish to congratulate you for an excellent tutorial on CSE. You have explained things far more clearly than even the official site of Google.
Understanding context and annotation was otherwise not easy.

Thanks a lot for such a good tutorial. We would look for more .

By the way I have a CSE on Life Science Search Engine, and have defined many labels . I am wondering if I can have sub-labels also i.e labels within labels.

Kindly check the site at:

http://www.brij.in/

Thanks again for a wonderful learning expereince you provided.

Brij