Defining and non defining relative clauses

In the following link, you have an explanation of these clauses, and after that, some exercises to practice:

http://learnenglishteens.britishcouncil.org/grammar-vocabulary/grammar-videos/relative-clauses

If you want/need more practice, you can use these links:

http://www.englishexercises.org/makeagame/viewgame.asp?id=4219

https://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?04

https://www.ego4u.com/en/cram-up/grammar/relative-clauses/exercises?12

Finally, and a bit more difficult, in these links you have to join two sentences into one, using defining and non defining clauses:

http://www.perfect-english-grammar.com/relative-clauses-exercise-1.html

http://www.perfect-english-grammar.com/relative-clauses-exercise-2.html

http://www.perfect-english-grammar.com/relative-clauses-exercise-3.html

http://www.perfect-english-grammar.com/relative-clauses-exercise-4.html