請幫忙改成正確寫法?

think of (X) --- think up (invent something in your mind)
really (adv) --- missing an adjective after it
be upsetting --- be upset (passive voice) ....+ to-finitive

改寫成 :
I once knew someone, who had thought up a really effective classroom technique which he presented at a conference, only to be upset to see someone else use it afterwards.

I once knew someone who got upset seeing his classroom technique, that he presented in a conference, being used afterward (without crediting him properly.)

Why was he upset? I thought the purpose of presentation in conferences is to publish your ideas!

I knew someone who got upset (n)---1
after the conference-----2
that his classroom technic-----3
has been used afterwards-----4
without due credit.where credits are due.-----(5)
upset:-
eg:-It upset(v) him to think of his classroom technic all had been stolen.
eg:-It upset(v) him that nobody had bothered to tell him about his credited classroom technic.
eg:-Don't be upset(v) himself about it, but prosecute to Education and Police Department concern.
eg:-An upsetting (adj)experience making him feel annoyed due to no credit mentioned !?

Amendment: I once knew a teacher who had a good method to maintain class-discipline, but he was upset when someone plagiarized that method. Yip