Min,
You can use the nominalization list to count how many times students used those words in their written work. You need to put each nominalization word in a include file, one word per line, and then run FREQ command with +
s...@nominalization.cut option. This assumes that you call the nominalization list file "nominalization.cut". The format of the "nominalization.cut" file depends on whether you are looking for words on speaker tier or lemmas of words on %mor tier. For speaker tier search just use the words as they appear on speaker tier. For %mor tier search use +sm option format. You can run command "freq +sm" to see more information about this format or read more about it in CLAN manual. Here is a short example of %mor include file format:
m;do
m;be
m;there
m;it
This will look for stems/lemmas of speaker's tier words "do", "be", "there" and "it", but on %mor tier. The prefix "m;" indicates that you want CLAN to search on %mor tier.
If you have any questions about this, then please email to me directly with your data sample file and I will try to give you a more precise suggestion of how to accomplish what you want to do.