# Relative clauses (defining or non-defining)

There is a question in a test as follows:

Combine these two sentences into one with a relative clause:

My brother is a great doctor.
He works in a famous hospital

My friend insists that there is only one way to do this based on the question, which is:

My brother, who works in a famous hospital, is a great doctor.

He also said things about defining and non-defining clauses to support his opinion, but to be honest I didn't understand.

My brother is a great doctor who works in a famous hospital.

• Your friend is ignorant. The last version is the "default" construction in English. You can tell that simply from the fact that it doesn't require any punctuation / special enunciation to get the message across. Your friend's version requires commas (pauses in speech), otherwise people will think you're singling out specifically the brother who works in a famous hospital as a great doctor (implying that you have other brothers who don't work in famous hospitals who aren't great doctors). Commented Nov 28, 2023 at 18:26
• (Your friend is correct that the commas are needed if you've "inverted" the utterance to "front" the who- element. But the inversion itself is unnecessary.) Commented Nov 28, 2023 at 18:28

Both structures work in this case because the "who works in" clause is "non-defining." And your structure has the advantage of being more straightforward.

What your friend is thinking of is: if the clause were a "defining" one, then the structure he proposed would be right (but without the commas). Let's say you've seen several doctors already:

The person who you saw first is a great doctor.

Maybe the later ones were lousy.

In this case, "who you saw first" is a necessary clause; it explains who "that person" is. It defines them. The clue is that we don't put commas around it. But in the original example, "My brother, who works in a famous hospital, is a great doctor," the speaker hasn't added the "famous hospital" part to help us tell one brother from another. It's just a bit of extra information.

My fried insists that there is only one way to do this based on the question

Actually, there are many ways to do this:

• My brother who/that is a great doctor works in a famous hospital

• My brother who/that works in a famous hospital is a great doctor

• My brother, who is a great doctor, works in a famous hospital

• My brother, who works in a famous hospital, is a great doctor

• My brother working in a famous hospital is a doctor

In any case, if you don't use a comma, you define 'my brother'. Thanks to the 'who/that ...' part, it is clear who you are talking about. (Maybe you have several brothers)

If you use a comma, the ', who ...,' part is additional information. It can be removed and it will still be clear who you are talking about. (Maybe you have only one brother)