Main Difference – That vs Which
Many people find the usage of the two relative pronouns, that and which very confusing. The first thing to remember when you are using these two words is that they are mainly used with objects. With people, we mostly use ‘who’. The main difference between that and which is, ‘that’ is used with restrictive clauses and ‘which’ is used with nonrestrictive clauses.
When to use ‘That’
‘That’ should be always used with restrictive clauses. A restrictive clause is an adjective clause that provides essential information to a sentence by limiting or restricting the thing it refers to. To understand this concept better, look at the following example.
“The girl who started the fight came to apologize.”
In this sentence, “who started the fight” is a restrictive clause. This clause not only describes the subject but also identifies the subject, ‘the girl’. It adds essential information to the sentence, and without this clause, the meaning of this sentence is not complete.
Similarly, ‘that’ should always be used when we are adding essential information to a sentence. ‘That’ does not merely help to describe, but it helps to identify the preceding noun.
“Chairs that have cushions are more comfortable.”
“Tiles that have slippery surfaces are dangerous.”
“The team that won the trophy did not attend the prize-giving.”
“My pet dog has eaten the cake that I made last night.”
In the above sentences, each clause preceded by ‘that’ adds necessary information to the sentences. If these clauses are removed, the meaning will be incomplete. if we remove the restrictive clause “that have cushions” in the first example, the sentence will read as “Chairs are more comfortable.” However, this sentence does not mean the same as the original sentence and the meaning remains incomplete.
You can also note in the above examples that restrictive clause do not use commas.
* Though that is mainly used with non-human references, it can also be used to refer to human references as well. This usage dates back to the 11th century.
Ex: “Last night, we met somebody that I used to know.”
When to use ‘Which’
‘Which’ is generally used with non-restrictive clauses. A non-restrictive clause is a clause that provides additional information about its preceding noun.
“Johanna Adams, who was the prettiest girl in our class, got married last week.”
In the above sentence, the underlined section is a non-restrictive clause. It provides additional information about its preceding noun, Johanna. The meaning of the sentence will remain the same even if we remove the non-restrictive clause. Also, note that the non-restrictive is separated from the rest of the sentences through the use of commas.
Which is mainly used when additional information is being added to a sentence. In such instances, which is always preceded and/or followed by commas. Examples below will clarify these features further.
“I just heard that her mother has passed away, which saddened all of us.”
“Moon Stones, which are commonly found in Sri Lanka, are not very expensive.”
“Her house, which was built in 1955, was destroyed in the earthquake.”
Interchange – That vs Which
Despite the existence of this grammar rule, many people often use ‘which’ with both restrictive and non-restrictive clauses in the common usage. Look at the two examples below.
“Who stole the dress that I bought yesterday?”
“Who stole the dress which I bought yesterday?”
Many people would consider both these sentences grammatically correct. However, keep in mind that it is safer to use the traditional grammar rule in formal writing.
In addition, although ‘which’ can be used with both restrictive and non-restrictive clauses, ‘that’ can be used only with restrictive clauses.
Though the meaning of certain sentences remains largely unchanged when these two words are unchanged, and can be accepted as correct, a change of meaning can be noted in some sentences. For example,
“The painting that was hanging in his bedroom was stolen.”
“The painting, which was hanging in his bedroom, was stolen.”
The first sentence specifically says that it was the painting in the bedroom that was stolen. It connotes that there was only one painting in the bedroom. If there were more than one painting in the bedroom, the use of ‘that’ in this sentence would be incorrect.
But in the second sentence, it does not specifically say that there was only one painting. If there was only one painting in the bedroom, this sentence would be incorrect.
Difference Between That and Which
The best way to distinguish the difference between that and which is to determine whether the clause you are writing is a restrictive clause or a non-restrictive clause. If it is a clause that adds essential information to the sentence, it is a restrictive clause, and you should use ‘that’. If it is a non-restrictive clause, which adds additional information to the sentence, then you should use ‘which’. Another difference between that and which is, that is not surrounded by commas whereas which is surrounded (preceded or/ and followed) by commas. In addition, it is sometimes acceptable to use which with both restrictive and non-restrictive clauses, but that cannot be used with non-restrictive clauses.