In learning English, it is common to encounter difficulties in distinguishing between the relative pronouns "which" and "that". Although both translate into English as "which" and are used to introduce subordinate clauses, their correct use depends on the type of information they contribute to the main sentence. Understanding this difference is essential for constructing precise and clear sentences in English.
Defining and Non-Defining Clauses
To understand when to use "which" or "that", it is essential to know the difference between "which" and "that". defining clauses (restrictive relative clauses) and the non-defining clauses (non-restrictive relative clauses).
1. Defining Clauses
These are subordinate clauses that provide essential information about the noun to which they refer. Without this information, the meaning of the main sentence would be incomplete or ambiguous.
Example:
The book that is on the table belongs to Sarah.
(The book on the table belongs to Sarah.)
In this sentence, the clause "that is on the table" specifies which book we are referring to. Without this information, we would not know what the book in question is.
2. Non-Defining Clauses
These are subordinate clauses that add additional or incidental information about the noun, but which is not essential to understanding the main meaning of the sentence. These clauses are usually enclosed in commas.
Example:
My car, which I bought last year, is very reliable.
(My car, which I bought last year, is very reliable).
Here, the clause "which I bought last year" provides extra information about the car, but even without it, the main sentence "My car is very reliable" is still complete and understandable.
Use of "That"
"That" is mainly used in defining clausesThe subordinate clauses, i.e. those subordinate clauses which provide essential information to identify or specify the noun to which they refer. These clauses are not separated by commas.
Examples:
The house that has a red door is mine.
(The house with the red door is mine).Students that study hard usually get good grades.
(Students who study hard tend to get good grades).
In both cases, the clauses introduced by "that" are essential to identify which house or which students we are talking about.
Use of "Which"
"Which is used in non-defining clausesi.e. in subordinate clauses that add additional information about an already identified or known noun. These clauses are separated by commas and their omission does not alter the main meaning of the sentence.
Examples:
The Eiffel Tower, which is located in Paris, is a popular tourist attraction.
(The Eiffel Tower in Paris is a popular tourist attraction).My laptop, which I bought last month, is already malfunctioning.
(My laptop, which I bought last month, is already crashing).
Differences in Usage between British and American English
There are differences in the use of "which" and "that" between British and American English. While American English strictly prefers the use of "that" for restrictive clauses and "which" for non-restrictive clauses, in British English it is more common to use "which" in restrictive clauses without this being considered incorrect. However, to maintain clarity and consistency in writing, it is advisable to follow the traditional distinction between the two terms.
Practical Tips for Remembering the Difference
Identify the importance of information: If the information is essential to identify the noun, use "that". If it is additional and not essential, use "which".
Use of commas: Clauses introduced by "which" are usually enclosed in commas, whereas clauses introduced by "that" are not.
People vs. things: Although both "which" and "that" are used for things, it is more common to use "who" or "that" to refer to people, but not "which".
Example:
The teacher that inspired me the most was Mr. Smith.
(The teacher who inspired me the most was Mr. Smith).
Common Mistakes and How to Avoid Them
1. Interchanging "which" and "that" incorrectly
Using "which" in a restrictive clause without commas can cause confusion. It is preferable to use "that" in such cases.
Incorrect:
The book which is on the table belongs to Sarah.
Right:
The book that is on the table belongs to Sarah.
2. Omitting commas in non-restrictive clauses
Not placing commas around a clause introduced by "which" can alter the meaning of the sentence.
Incorrect:
My car which I bought last year is very reliable.
Right:
My car, which I bought last year, is very reliable.
Importance of Accuracy in the Use of "Which" and "That".
Accurate use of "which" and "that" not only improves clarity of communication, but also reflects a more advanced command of the English language. Mastering this difference will help to avoid misunderstandings and improve both writing and speaking in English.
Practical Exercises
To reinforce learning, here are some exercises:
Complete the following sentences with "which" or "that":
The movie ____ won the Oscar was amazing.
The laptop, ____ I bought yesterday, is already malfunctioning.
The restaurant ____ we visited last night was excellent.
Identify whether the following sentences contain defining or non-defining clauses:
The painting, which was created in the 18th century, is very valuable.
The book that is on the shelf belongs to John.
- Solutions: 1: that / which /that. 2: which (Non-defining clause) / that (Defining clause)
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