Great! Thanks a lot for your help!
You know, I'm a native speaker but sometimes I just can't think of the simplest things.
Especially where letter-writing is concerned. I just wasn't sure if one can "portray a situation" or if the only correct form is to portray "a character."
Well, about the appendicitis thing, my sentence goes somehow like this.
....... you're not only a great actress, but you could also make use of the skills you learned in the hospital outside the ER, as in diagnosing appendicitis(es).
Clearly for any other words there should be the plural here, like "as in helping PEOPLE" or "as in diagnosing problemS"
Any ideas?
Thanks!
Walt