Defining vs Non-defining Relative Clauses (use of commas)

This swimming pool is for people_ who can't swim very well. (comma or no comma for _?)

• comma

• no comma

Martha_ who is a very good student_ won first prize in Maths. (comma or no comma for _?)

• comma

• no comma

Laura likes the necklace_ that her parents gave her. (comma or no comma for _?)

• comma

• no comma

My back_ which had hurt all day_ was still painful that evening. (comma or no comma for _?)

• comma

• no comma

James is someone_ who always tries to do well at everything. (comma or no comma for _?)

• comma

• no comma

My neighbour Simon_ who is very intelligent_ teaches Physics. (comma or no comma for _?)

• comma

• no comma

We took the train to Paris_ which is a city I love. (comma or no comma for _?)

• comma

• no comma

The hotel_ which we stayed in_ was small but comfortable. (comma or no comma for _?)

• comma

• no comma

Ian's father_ whom he hadn't spoken for ages_ called last night. (comma or no comma for _?)

• comma

• no comma

Jason_ whose father called last night_ lives in Portugal. (comma or no comma for _?)

• comma

• no comma