Clarifying the Use of 'That' vs 'Which' in English: A Comprehensive Guide

When it comes to English language grammar, the correct usage of the pronouns 'that' and 'which' can sometimes be confusing. While both can be used in relative clauses to add additional information to a noun, their applications differ based on whether the information is necessary or not. In this article, we will explore the distinctions between 'that' and 'which' and how they affect the understanding of sentences.

The Role of 'That'

'That' is typically used to provide necessary information, helping to identify or specify the noun to which it is referring. This is often referred to as a defining or non-essential relative clause. For example:

The book that you lent me is lost.

In this sentence, the clause 'that you lent me' is essential to clearly identify which book is being referred to. Without this information, the sentence would lack clarity.

The Role of 'Which'

'Which' is used for information that is not necessary to the understanding of the sentence, making it a non-defining or non-essential relative clause. In these cases, the comma separates the relative clause from the rest of the sentence, indicating that it is additional information:

The Eiffel Tower, which is now the main tourist attraction in Paris, was constructed between 1887 and 1889.

Here, the clause 'which is now the main tourist attraction in Paris' does not change the core meaning of the sentence about the Eiffel Tower's construction dates.

Application to Smokers and Smoking

This distinction becomes particularly relevant when discussing negative behaviors such as smoking. Consider the sentence:

One should quit smoking that is harmful to health).

This phrasing is awkward because 'smoking that is harmful to health' implies that there are different kinds of smoking, some of which may be beneficial, which is clearly false. Instead, we should use:

Smokers should quit smoking because it is harmful to their health.

This revised sentence uses an adverb clause of reason to provide the logical reasoning for why smokers should quit smoking. It explicitly states that all kinds of smoking are harmful, reinforcing the idea that there is no distinction to be made.

Conclusion

Understanding the correct use of 'that' and 'which' is crucial for clear and effective communication in English. By using these relative pronouns appropriately, you can enhance the readability and comprehension of your writing. Remember, 'that' is used to provide essential information that helps identify or specify a noun, whereas 'which' is used to add non-essential information. Proper usage not only improves clarity but also adheres to the conventions of English grammar.