What Every Student Should Know About 'That' in English Grammar

So, you're staring at a graded English test, seeing a red mark next to a sentence that feels perfectly natural, and wondering if your teacher is actually right. The sentence in question is: "It is believed the hamburger was invented in Texas." Your teacher says it's wrong because you left out the word that. You're left wondering, "Wait, do I actually need that word here, or is this just an arbitrary rule?"

Does omitting "that" actually break the rules of English?

Let's look at a scenario I dealt with a few years ago. I had a student named Marcus, a sophomore History major who was writing a thesis on the Industrial Revolution. He wrote a sentence: "Many historians argue the steam engine changed everything." When he turned in his first draft, his TA marked it as a grammatical error, insisting it should be "argue that the steam engine..." Marcus came to my office hours looking completely defeated, convinced he had forgotten a fundamental rule of English. He told me, "I say it this way every day. Why is it wrong on paper?"

Here is the honest truth: your sentence is not ungrammatical. In linguistics, we call this "that-deletion" or "zero complementizer." In English, the conjunction that is often optional when it introduces a noun clause, especially after verbs of thinking, believing, or saying. Whether you say "I think that it's raining" or "I think it's raining," the meaning is identical and the structure is sound.

In your specific sentence, "It is believed the hamburger was invented in Texas," the word that is acting as a bridge between the main clause (It is believed) and the subordinate clause (the hamburger was invented in Texas). In modern English, that bridge is often invisible. If you read a newspaper, a novel, or a high-quality journal, you will see this omission thousands of times. It is a standard feature of the language, not a mistake.

"But my teacher said it's wrong. If I'm writing for a grade, does 'correctness' even matter if the person grading it disagrees?"

That is the million-dollar question in academia. There is a difference between prescriptive grammar (the rigid rules found in old textbooks) and descriptive grammar (how the language is actually used by educated speakers). Your teacher is following a prescriptive approach. While they might be technically outdated, they are the ones holding the red pen.

The actionable takeaway here is that your sentence is grammatically acceptable in almost every real-world context, but it may be considered "informal" by strict traditionalists.

Why would a teacher insist on including "that"?

Imagine Sarah, a first-year Pre-Med student. She's incredibly bright but writes in a very conversational style. In her lab reports, she often wrote things like, "The results suggest the hypothesis was incorrect." Her professor kept adding that back into her sentences. When Sarah asked why, the professor explained that in scientific writing, clarity is king. By adding that, you create a clear signal to the reader that a new clause is starting. It prevents the reader from momentarily misinterpreting the sentence.

This is likely what your teacher is thinking. When you use a passive construction like "It is believed," the sentence is already a bit formal and detached. Adding that maintains that formal tone. Without it, the sentence feels slightly more casual. In a classroom setting, teachers often push students toward the most formal version of English to prepare them for academic journals or professional legal documents where ambiguity can be costly.

There is also the issue of "garden path sentences." These are sentences that lead the reader down one mental path, only to reveal at the end that the path was wrong. For example, if you write "I believe the man is lying," it's clear. But in more complex sentences, omitting that can occasionally cause a momentary stumble for the reader. Your teacher might be applying a "blanket rule" to avoid these rare errors, even if your specific sentence about hamburgers is perfectly clear.

To help you navigate this, consider this decision framework for when to keep or cut the word that:

The actionable takeaway is that while the omission isn't a "error," including that acts as a safety net for formality and clarity.

How do you handle the disagreement with your instructor?

I remember a student named Leo, a junior in Political Science, who had a similar clash with a professor. Leo was a bit of a perfectionist and wanted to prove he was right. He went to the professor with a printed list of examples from The New York Times showing that that was omitted in professional writing. It didn't go well. The professor felt attacked and viewed Leo as arrogant rather than inquisitive. Leo ended up with a lower grade on the next paper, not because of his grammar, but because of the friction in the relationship.

When you're in this position, you have to play the "academic game." You aren't just learning English; you're learning how to navigate professional hierarchies. If you want to challenge the grade, do it with curiosity, not a "gotcha" attitude. Instead of saying, "You're wrong, this is actually grammatical," try saying, "I noticed in some of my readings that that is often omitted in these cases. Could you help me understand the specific rule for this class so I can be consistent in the future?"

This approach does two things. First, it signals to the teacher that you are an engaged student who reads widely. Second, it puts the burden of proof on them to explain the rule. If they can't point to a specific style guide (like MLA, APA, or Chicago), they might realize they were being overly rigid and give you the point back. If they do point to a guide, you've just learned exactly what that specific teacher expects from you, which is the most valuable piece of information you can have for the rest of the semester.

"I just hate feeling like I'm being lied to about how the language works. If it's not actually wrong, why am I being penalized?"

It's frustrating, I know. But remember that language is a living thing, and textbooks often lag behind reality by twenty or thirty years. Your teacher isn't necessarily lying; they are likely reciting the version of English they were taught to value. In the professional world, the "correct" version of a sentence is often whatever your boss or your editor prefers. Learning to adapt your style to your audience is a higher-level skill than simply following a grammar rule.

The actionable takeaway is to frame your question as a request for guidance on "style" rather than a correction of "grammar."

Wait, what about the "Passive Voice" issue?

While we're talking about this sentence, we have to address the elephant in the room. Your teacher might be reacting to more than just the missing that. The phrase "It is believed..." is a classic example of the passive voice. It's a way of stating something without saying who actually believes it. In many writing centers, we see students use this because it sounds "academic," but it can actually make writing feel hollow or evasive.

Take Maya, a first-year Sociology student. She wrote a paper where every second sentence started with "It is thought that..." or "It is believed that..." Her professor told her the paper felt like it was written by a ghost. When Maya switched to "Historians believe..." or "Current research suggests..." her writing immediately gained authority. The sentence became active and grounded.

It's possible your teacher is subconsciously annoyed by the passive construction and is focusing their critique on the missing that because it's an easier "rule" to point to. If you want to truly impress a writing instructor, don't just add the conjunction; look at the whole structure. Instead of "It is believed that the hamburger was invented in Texas," try "Many believe the hamburger originated in Texas." You've removed the clunky passive opening and the debate over that vanishes entirely.

Of course, there are times when the passive voice is necessary—like when the "believer" is unknown or irrelevant. But in a school test, teachers are often looking for you to demonstrate a command of active, clear prose.

The actionable takeaway is to check if your "grammatical" struggle is actually a "style" struggle in disguise.

Is there a definitive "Yes" or "No" answer here?

If you were taking a linguistics exam at a university, the answer would be a resounding Yes: the sentence is grammatically correct without that. If you are taking a test for a teacher who adheres to strict, traditional prescriptive grammar, the answer for that specific classroom is No.

Let's look at the actual mechanics one last time. In the sentence "It is believed (that) the hamburger was invented in Texas," the word that is a complementizer. Its only job is to signal that a clause is following. Because the word the (the start of the next clause) is so distinct, the signal isn't strictly necessary for the brain to process the sentence. This is why we can drop it. We do the same thing with "I know (that) you're tired" or "She said (that) she'd be late."

If you're feeling anxious about your grade, just remember that this is one of the most common points of contention between students and teachers. You've stumbled upon a classic tension in the English language: the gap between the rules we are taught and the way we actually communicate. You aren't "bad at English" for omitting the word, and your teacher isn't "wrong" for wanting the most formal version possible. You're just seeing two different versions of the same language.

The actionable takeaway is to accept that in English, "correctness" is often a matter of context and audience rather than a binary true/false.

At the end of the day, don't let a red mark on a test about hamburgers make you second-guess your intuition. Your instinct was right—the sentence works. But now you know the "secret" of academic writing: sometimes, adding a few unnecessary words is the fastest way to get an A. Just keep an eye on who is grading your paper, adjust your "formality dial" accordingly, and keep writing. You've got this.