1. Defining relative clauses Non-defining relative clauses
Look! There’s the waiter
who works at the bar where I have breakfast.
The relative clause contains essential information.
No commas
You can use “that” instead of “who” or “which”.
The relative pronoun can be omitted if it is the object of the verb in the relative clause.
I’m enjoying the book (which/that) you lent me.
Non-defining relative clauses
Their new house, which has five bedrooms and a games room, is much larger than their old one.
You need to put commas before and after the relative clause.
“that” cannot be used

2. Participle Clauses
Present: Ing form , + clause Opening the door, I saw that we had been robbed. = to describe something happening at the same time as the action or immediately after it. Prepositions and conjunctions + ing form After watching the film, I was too scared to go to bed. You can take the train instead of catching a taxi. Perfect participle Having + past participle , + clause = to describe something that happened before the main action. It may provide a reason for that action Having left our map at home, we got lost.
Passive
Use a past participle clause when the meaning is passive.
Drunk in small quantities, red wine can be good for you.
Used instead of relative clauses
ING form = when the meaning is active
There are three pictures hanging on the wall. = (there are three pictures which are hanging on the Wall)
PAST PARTICIPLE = when the meaning is passive
Anyone caught shoplifting will be prosecuted. = ( anyone who is caught shoplifting will be prosecuted)