Defining Relative Clause
The girl (who/that) you were introduced to at the party went to college with me.
The apartment where you stayed on your last vacation belonged to a famous artist.
I like it when the day is rainy.
Non-defining Relative Clause
Robin Williams, who won several Academy Awards, passed away in strange circumstances.
Former President Trump, one of America’s most polemic leaders, is being accused of fraud.
We ordered a state-of-the-art gaming console, although we had to wait for 2 months for its
delivery.