I am from Thailand. I would be very much appreciate if you could explain about the easy rule of reducing clauses. It is very hard to remember.
I very much appreciate your kindness.
I didn't know that there was an easy rule for reducing clauses, Ampaiwan, but generally the relative pronoun and auxilary verbs or 'be' forms can be omitted, as well as some conjunctions:
The man [who is] sitting next to me is as bald as an egg.
[While I was] sitting on the bench, I peeled an orange.
[Having been]once bitten, he was twice shy.
My barber, [who has]never [been] a shirker, cuts hair 14 hours a day.