How to use – That and Which
In the use of essential information, use that.
In the use of non-essential information, use which.
Non-defining clause (non-essential information) only provides excess information. If you remove them they don’t change the meaning of the sentence. They are almost always used with a comma.
For example, “I like cars, which are also fast.” Here the meaning of the sentence is that he likes cars in general but he also likes fast cars.
Defining clause (essential information) provides essential information.If you remove them, the meaning of the sentence changes.
For example, “I like cars that are fast.” Here the meaning is that he likes fast cars. “That” is used to explain what kind of cars he likes.
THAT- Used as a clause containing ‘essential’ information about the noun that comes before it.
E.g.: She wiped all the milk that was spilled on the floor.
In this sentence, the essential information about the noun ‘milk’ is that it was spilled on the floor. If we try to omit the clause ‘that’ here, the meaning may look incomplete and can be comprehended in a number of ways.
E.g.: She wiped all the milk.
If you leave out this type of ‘restrictive relative clause’, the meaning of the sentence is affected—indeed, it will result in either a sentence of doubtful meaning or a sentence that makes no sense at all.
WHICH – Used as a clause containing ‘extra’ information that could be left out of the sentence without affecting the meaning or structure.
E.g.: She called out for her dog, which was missing since morning. In this sentence, the extra information about the subject ‘dog’ is that it was missing since morning. Now, if we omit the clause ‘which’ here, the meaning is more or less comprehensible. Alas! The lady is calling out or shouting out for her pet.
E.g.: She called out for her dog. Remember, non-restrictive relative clauses can be introduced by which, whose, who, or whom, but you should never use ‘that’ to introduce them.
The ‘which’ clause is usually preceded by a comma, setting off the extra information, whereas no comma precedes restrictive clause ‘that’, indicating that the information is essential, not extra.
Let’s brush our skills to understand the usage of who, which and that through the exercise given below:
Exercise: Who/ That/ Which
- He is the man ___________ wants to marry my sister.
- The boy ___________ bought my car is very rich.
- The only thing __________ matters is your exam.
- This idea , _________ changed the world, was great
- Everything _________ moves is scaring here.
- I met a woman _________ can speak Chinese.
- What’s the name of the man ___________ lives next door?
- What’s the name of the river ___________ goes through the town?
- Everybody ___________ went to the party enjoyed it very much.
- Do you know anybody ____________ wants to buy a car?
- Where is the clock “that / which” was on the wall?
- She always asks me questions, __________ are difficult to answer.
- I have a friend ___________ is very good at singing.
- I like people ____________ speak well.
- Have you seen the dictionary ____________ was on the table?