That, Which or Who?!

My sister, who I love a lot, has a big sweater that has many holes, which get bigger every time she wears it.

Have you ever been confused by when you use that, which or who to describe the subject of your sentence? So were the students in the English class I am currently teaching! However, with the handy chart below and some easy steps, it’s easy to figure out which word to use in your descriptive clause.

Subject Punctuation   Type of Information
Place/Thing  None That Defining

Which Non-defining
Person None Who Defining



STEP 1: Find the Subject

The sentence above has two different subjects that are described by clauses. The first subject of the sentence is “my sister,” then the second is “a big sweater.”

STEP 2: Determine the Type of Noun

Is the subject of your sentence a person or a place/thing? The first subject, “my sister” is a person noun while the second noun, “a big sweater” is a thing.

STEP 3: Determine the Type of Information

Defining information is anything that is necessary to provide so that your reader can understand what the subject is. Meanwhile, non-defining information simply gives extra detail and could be taken out of the sentence easily. For example, the information that the sweater has many holes is necessary to identify this specific sweater. On the other hand, the fact that the holes get bigger each time your sister wears the sweater does not define the sweater and is extra detail.

STEP 4: Choose Your Word Using the Chart. Click here to download it from our Resources page.

STEP 5: Add Punctuation.

While you might get by when speaking using any of these words, it’s best to be correct in writing 🙂 This is even more important when adding in the correct punctuation. Non-defining clauses should be surrounded by commas “,” the punctuation marks that indicate a pause in the sentence. These marks also indicate that the clause could be excluded from the sentence and still make sense. For example, in the sentence above, you could take out “who I love a lot,” and the sentence would still be grammatically correct!

In this type of sentence, which will always come after a comma, but who either has a comma before or does not depending on whether the information is defining or non-defining. 

Have questions? Contact us, we’d love to hear from you!


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