That/Which

Introduction

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To understand the concept, the first thing that we must understand is, ‘that’ and ‘which’ are not synonymous at all. Though both of them are pronouns, yet they cannot be used interchangeably.

The basic difference between them is that ‘which’ introduces a non-essential clause, whereas ‘that’ introduces an essential clause.

Now, to get a little more clarification on the subject, we must understand the concepts of essential and non-essential clauses.

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So, what is an essential clause and a non-essential clause?

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An essential clause is a clause essential to the meaning of the sentence. It is also known as restrictive.

For example, the forest that caught fire last week is still burning.

In this sentence, notice how the clause “caught fire last week” is essential as it identifies the forest that is still burning.

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In the same way, a non-essential clause is a clause that is not essential for the meaning of the sentence.

For example, the black pen I found, which was lying on the table, is so fine.

In this sentence, the phrase ‘was lying on the streets’ is not essential to identify the pen when removed. The sentence will still refer to the black pen that the speaker found.

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In conclusion, we can say that the clause that comes after the word ‘which’ or ‘that’ will determine the use of them. If any sentence has a clause that is not needed ‘which’ can be used, whereas if the clause is important, ‘that’ must be used.

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