On the journey to mastering English, correctly using complex grammatical structures is key to elevating your writing style, especially in academic exams like IELTS. One structure that often causes confusion but holds immense expressive power is the relative clause using 'which' to refer to a whole preceding clause. This is not just a common grammar point, but a tool that helps you express opinions and comments with subtlety and naturalness. This article will delve into this special use of 'which', helping you master a crucial skill for more fluent and professional writing.

What is a 'which' clause that modifies an entire sentence?

Typically, we know 'which' as a relative pronoun used to replace a noun referring to a thing that comes right before it. However, in a more advanced structure, 'which' can be used to modify the entire idea or event mentioned in the preceding main clause. In this case, 'which' no longer just replaces a single noun; it represents a whole situation, action, or statement.

This is a special form of a non-defining relative clause, also known as a sentential relative clause, and it is always separated from the main clause by a comma. The use of a comma is mandatory because it indicates that the information provided by the 'which' clause is merely an additional comment or observation, not essential information for identification. This is a special type of Relative Clause with Which.

Example:

• He decided to quit his job without telling anyone, which surprised his family a lot.

In the sentence above, 'which' does not replace 'anyone' or 'job'. It replaces the entire fact that 'he decided to quit his job without telling anyone'. The clause 'which surprised his family a lot' is a comment on that action.

When should you use 'which' to comment on a whole clause?

This structure is extremely useful when you want to make your writing more cohesive and profound. You should use it in the following cases:

• To make a comment, observation, or evaluation: This is the most common use. The 'which' clause allows you to express your feelings or opinions about the event just mentioned.
  Example: The government has increased taxes on fuel, which is likely to be unpopular with drivers.
• To show the result or consequence of an action: The 'which' clause can be used to smoothly connect an action to its direct result.
  Example: She practiced playing the piano for hours every day, which eventually led to her winning the national competition.
• To provide an explanation or additional information: Sometimes, you want to further explain the reason or context of an event.
  Example: There was a major accident on the highway, which explains why the traffic is so heavy this morning.

What's the difference between 'which' and 'that' in relative clauses?

This is a crucial grammar point that often leads to confusion. The core difference lies in the function of the relative clause: defining (restrictive) versus non-defining (non-restrictive).

• Defining relative clauses (using 'that' or 'which'): Provide essential information to identify which person or thing is being talked about. These clauses are not preceded by a comma.
  Example: The report that I submitted yesterday was approved. → If you remove the clause 'that I submitted yesterday', the listener wouldn't know which report was approved.
• Non-defining relative clauses (only using 'which'): Provide extra, non-essential information. These clauses are always preceded by a comma.
  Example: The final report, which was over 50 pages long, was finally approved.

Most importantly, when 'which' is used to modify an entire sentence, it is always non-defining and must be preceded by a comma. You can never use 'that' in this case.

Incorrect: He forgot her birthday again, that made her very upset.
Correct: He forgot her birthday again, which made her very upset.

How do you use commas with sentential relative clauses?

The rule for commas in this case is simple and consistent: Always place a comma (,) before 'which' when it modifies the entire preceding clause.

This comma acts as a short pause in the sentence, signaling to the reader that the following part is a subordinate idea, an additional comment. Omitting the comma would completely change the meaning of the sentence, causing 'which' to be misunderstood as modifying only the noun immediately preceding it.

Consider the difference:

• He didn't come to the meeting, which was a pity. → 'which' refers to the whole fact that 'he didn't come to the meeting'.
• He didn't come to the meeting which was held yesterday. → 'which' only modifies 'the meeting'. This sentence is missing a comma and, grammatically, using 'that' would be more natural.

How can this structure be applied in the IELTS Writing test?

Proficiently using this structure is an excellent way to score points in the 'Grammatical Range and Accuracy' criterion of the IELTS test. It demonstrates your ability to construct complex sentences naturally and logically. This is a key piece of Advanced IELTS Grammar that you should master.

In IELTS Writing Task 1 (Academic):

When describing a chart or graph, you can use this structure to comment on a trend or a notable figure.

• The sales of electric cars doubled between 2015 and 2020, which indicates a significant shift in consumer preferences.

In IELTS Writing Task 2:

When writing an essay, this structure helps you link ideas, present consequences, or comment on an argument fluently.

• More people are choosing to work from home, which reduces traffic congestion in major cities and has a positive impact on the environment.

Conclusion

Using the 'which' clause to modify an entire sentence is a sign of linguistic maturity. It not only makes your sentences richer and more varied but also demonstrates your ability to think logically and connect ideas cohesively. Start practicing by looking for this structure in English reading materials and creating your own sentences with it. Gradually, you will be able to apply it naturally and accurately, making a significant difference in your writing skills.

Related Posts:

• Mastering 'It depends...': A Guide to Using Conditional Sentences
• How to Use 'Actually' for Natural and Polite Corrections
• Using 'The reason why...' Structure for Coherent Explanations