'When' or 'That'

19 April 2024

Hello! This week on Ask a Teacher, we answer a question that sanjibganguli3084 posted on our YouTube channel.


Ma,am, which of the following sentences is grammatically correct? -It was last Saturday that we met him/It was last Saturday when we met him.


Thank you for writing, Sanjib. This is a very good question.

We talked about relative pronouns in an earlier Everyday Grammar article. The article explains that relative pronouns help identify or give more information about a noun.

English has many relative pronouns. Most relative pronouns are the same as question words: who, which, whose, whom, where, when, and why. That is also a relative pronoun.

Often, there is more than one grammatically acceptable relative pronoun. For example, we can say:

I have more friends who are boys.

This is something which everyone knows.


I have more friends that are boys.

This is something that everyone knows.

All the sentences are grammatically correct.

Usually, choosing the best pronoun depends on the usage. In spoken English, we use "that" more often than other relative pronouns. In academic written English, we use "which" more often than other relative pronouns. In news writing, we use "which" and "who" the most.

Sanjib, you asked about "that" or "when." We do not use "when" as a relative pronoun very often. We sometimes use "when" with expressions of time. For example,

There are a lot of times when we disagree.

But more often, we do not use a relative pronoun.

There are a lot of times we disagree.

So, either of your sentences is grammatically correct. But most of the time in English, we would use "that" in your sentence, especially if it were spoken.

We hope this explanation has helped you, Sanjib.

Do you have a question about American English? Send us an email at learningenglish@voanews.com.

And that's Ask a Teacher.

I'm Gena Bennett.

Gena Bennett wrote this lesson for VOA Learning English.


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academicadj. related to schools and education