and then the editor takes it out
Article by Mary Hazelton
Relative clauses are subordinate clauses introduced by one of the following words: who, which, whose, whom, that, and phrases such as of whom, to which, etc.
There are basically two kinds of relative clauses - defining (qualifying, or limiting), and non-defining (non-qualifying or non-limiting).
1. Defining
The man who delivered the parcel was not from the Post Office.
Defining relative clauses are essential to the meaning of the sentence. If we take out the relative clauses from the examples above, we must ask the speaker for more information in order to understand the sentence. In other words, these relative clauses are closely linked to the word they describe and a comma would break that connection. Another good test it to say them out loud - these clauses are said without a pause before the which or that.
2. Non-defining
The new houses, which have electricity and running water, are all occupied.
Non-defining relative clauses give additional information about a person or thing. They are seldom found in speech, where we would be more likely to use and or to make a separate sentence. If you say them out loud, there is a natural pause before the extra information.
3. Co-ordinating
Sometimes a relative clause beginning with which refers to the whole of the previous clause (or longer section), not just the preceding word. This clause may describe a fact or concept. Compare the following sentences:
Unless a company adopts the school, which is in very poor condition, the children will have to go
In the first of these two sentences, which refers to the school - this is an ordinary non-defining relative clause. In the second which refers to the possibility that a company will adopt the school - this is a co-ordinating relative clause. These clauses can be considered a subset of non-defining clauses, but the comma is probably even more crucial. All such clauses are introduced by which.
Options
It is in fact true that not many defining relative clauses are introduced by which or whom. In some constructions alternatives are possible. Consider the following examples:
The book which I bought yesterday is damaged.
The reasons which he gave were not convincing.
He married a girl whom he met at univeristy.
In each case the first example of the three sounds over-formal and the alternative structures are much more natural. But inserting a comma before which or whom would completely change the meaning. And in academic writing the first construction occurs quite often. For example:
The data on which this product is based …
For this reason the grammar check is not right to insist on a comma before which. While it is true that which is more likely to introduce a non-defining or co-ordinating clause, it does not help to insert a comma if you intend a defining clause. Rather change which to that, or stick to your guns. (The grammar check is correct, however, in not allowing a comma before that. This would be contradictory - that suggests a closer link and the comma a less close link.)
[This article was added to the Web-site on 2 January 2005]
The kettle that I bought last month is already broken.
The students whose families had an income of less than R1 000 a month struggled to keep up with
their peers.
The number of households which do not have electricity is decreasing.
My brother, who works in Durban, is visiting us this weekend.
to school in town next year.
Unless a company adopts the school, which seems unlikely, the children will have to go to school
in town next year.
The book that I bought yesterday is damaged.
The book I bought yesterday is damaged.
The reasons that he gave were not convincing.
The reasons he gave were not convincing.
He married a girl that he met at university.
He married a girl he met at university.
The discs which you have purchased …
The group which reported that they had not worked for three months were questioned further
about their job-seeking activities.