that

"That" is one of those words we use so often that we rarely stop to think about what it actually does. It can point to something, link ideas, or add an important detail. It is small, but it does a great deal of work in everyday English.

One common use is pointing to a specific person, thing, idea, or time: "I want that apple, not this one." It is often used for something farther away than "this," whether the distance is physical or more about time and thought. You might point across the street and say, "That is my favorite shop." You might also talk about the past and say, "That was a good day."

Another common use is linking a statement to what someone thinks, knows, says, or feels: "She mentioned that she was tired," or "I am glad that you called." In many sentences, it introduces the idea that comes after the main verb. In informal English, people sometimes leave it out, as in "I think you are right," but the meaning stays much the same.

"That" is also used to show exactly which person or thing you mean: "The movie that we watched last night was amazing." Here, it introduces information that is necessary to identify the noun. This is why it is used in defining parts of a sentence, not in extra comments set off by commas.

It can also show degree or emphasis, as in "It isn't that simple" or "I didn't know it was that late." You will also meet it in fixed phrases and common patterns like "That's it" or "Now that you mention it." Because it has so many roles, the meaning depends on context. Whether it is pointing, linking, or narrowing the meaning, it helps make the speaker's message clear.