Defining and non-defining clauses

[Bassim]

My problems arise when I have to decide which relative clause is defining or non-defining. For example, in these sentences, I am wondering If I have written them properly:

1. The burglar entered the house through the window, which someone had left open.
2. I stumbled on the piece of old pipe, which remained after reparations.
3. I stumbled on the stone, which someone had left on the pavement.
4. I am reading the book which dates from 18th century.
5. The man showed me his watch, which he had inherited from his parents.
6. She sat looking at the vase, which she had received as a present for her birthday. ( do I need "which" at all in this sentence?)

 

[Bassim]

I am wondering if there is anyone who could help me with my question above. I would be grateful if someone would tell me where I make mistakes.

 

[5jj]

1. The burglar entered the house through the window, which someone had left open.
If there was only one window in the house, This is fine. If there was more than one, omit the comma - you are defining the window used for entry; 'a window' would be more natural.
2. I stumbled on the piece of old pipe, which remained after reparations.
If there has been previous mention of the pipe, then this is correct. If there hasn't, then its 'a piece of old pipe'. This is one of those not very common cases where both a defining and a non-defining clause are equally likely. 'Repairs' is a more usual word than 'reparations'.
3. I stumbled on the stone, which someone had left on the pavement.
Similar answer to #3.
4. I am reading the book which dates from the 18th century.
If there is more than one book, and only one dating from the 18th century, this is fine.
5. The man showed me his watch, which he had inherited from his parents. Fine.
6. She sat looking at the vase, which she had received as a present for her birthday. ( do I need "which" at all in this sentence?)
You need 'which' if it's a non-defining clause, but not if it's a defining clause.

You probably wouldn't need to bump your post if you asked about one sentence at a time. Some people are put off when they see five or six sentences requiring comments.

 

[Bassim]

5jj
Thank you for your help and your explanations. They have helped me to understand where I make the mistakes when writing these kind of sentences.

 

[5jj]

Thank you for your help and your explanations. They have helped me to understand where I make the mistakes when writing these kind of sentences.

:up:

I think that part of your problem lies with articles and context. If we already know something about the noun, then we are more likely to use a non-defining clause. It's difficult to illustrate without providing masses of context, but I'll try. Apologies for the rather stilted contexts, but I wanted to use one of your sentences.

A (on the phone): What are you doing at the moment?
B: I am reading a book [no comma] that (which) dates from the 18th century. (B is defining which book he is reading.)

A (on the phone): What are you doing at the moment?
B: I am reading a book, which is which is a collection of pages bound together, in case you've forgotten. (Sarcastic comment to a friend who hasn't read a book since he bought his first Kindle.)

A (on the phone): What are you doing at the moment?
B: I am reading a book, which is unusual for me. (It's the activity of reading a book that is unusual.)

A: I noticed you took out some books and papers from the library. Whch one are you reading at the moment?
B: I am reading the book [no comma]that (which) dates from the 18th century. (B is telling A that there is only one book dating from the 17th century)

A: I noticed that you took out one book and several journals from the library. Which one are you reading at the moment?
B: I am reading the book, which dates from the 18th century. (We know there is only one book)