1.2.3. Use: a) The Adjective Clauses can appear in a reduced form by leaving out the relative pronoun (who, which, that) and the "Verb to be". e.g. The man who is waving to us is the tour guide. The man waving to us is the tour guide. Waving to us, the man is the tour guide. The man who has waved to us is the tour guide. The man having waved to us is the tour guide. Having waved to us, the man is the tour guide. The letter that was written last two weeks arrived this morning. The letter written last two weeks arrived this morning. Written last two weeks, the letter arrived this morning. b) When there is no "Verb to be" in the Adjective Clause, the relative pronoun (who, which, that) is left out and the verb is changed into the ing form. e.g. I don't know the actor who appears on the stage. I don't know the actor appearing on the stage. I don't know the actor who has appeared on the stage. I don't know the actor having appeared on the stage. c) Not all Adjective Clauses can be in a reduced form. It cannot appear in a reduced form only if the relative pronoun (connector) is also a "subject." e.g. The woman that I saw yesterday is a dentist. Incorrect: The woman saw yesterday is dentist.