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TOEIC Part 5 · Reason signals

TOEIC Trap: Because vs Because Of vs Due To

Because, because of, and due to can all introduce a reason. The useful question is not “Which one means because?” It is what comes after the blank?

The event was cancelled because the weather was dangerous.

The event was cancelled because of dangerous weather.

The event was cancelled due to dangerous weather.

This page extends the simpler Because vs Because Of decision. If your problem is reason versus contrast, use Because vs Although.

The decision: complete reason idea or named cause?

because

Use it before a complete reason idea: the manager was absent.

because of

Use it before a named cause: the manager’s absence.

due to

Also works before a named cause and can sound more formal in business writing.

Do not use a timer rule. First identify what follows the blank, then choose the reason signal that fits.

Because: a complete reason idea follows

The meeting was postponed because the director was unavailable.

The order was delayed because the supplier sent the wrong parts.

The client approved the proposal because the estimate was reasonable.

You can see a complete reason: someone or something is doing, being, or experiencing something.

Because of: a named cause follows

The meeting was postponed because of the director’s absence.

The order was delayed because of a supplier error.

The client approved the proposal because of the reasonable estimate.

The words after because of name the cause rather than state a complete reason idea.

Due to: also before a named cause

Due to can mean because of. It is common in notices and business-style explanations, and it can sound more formal than because of.

The office will be closed due to building maintenance.

The delivery was delayed due to severe weather.

The event was cancelled due to low registration numbers.

The key point for this lesson is structural: due to + named cause, not a complete reason idea.

Why the original self-check needed repair

The source used because of and due to as separate answer choices in two sentences where both were valid. A one-answer practice item cannot score that safely.

Source-style ambiguity: The meeting was cancelled ___ the manager’s illness.

Both because of the manager’s illness and due to the manager’s illness are possible.

So the repaired checks below keep the teaching target but remove the competing valid answer from those two items.

Quick Part 5-style check

Feedback stays hidden until you choose. Check the words after the blank before you answer.

1. The meeting was cancelled ___ the manager was ill.
Source repair: the competing valid due to choice was removed.
2. The meeting was cancelled ___ the manager’s illness.
Source repair: the competing valid because of choice was removed.
3. Production stopped ___ a shortage of materials.
4. The invoice was rejected ___ the address was incorrect.

Learning Blocks: look for repeated evidence

One mistake on this page does not identify a Learning Block. Check whether the same pattern appears across several questions or practice sessions.

Translator

You treat all three expressions as the same translation and miss the form after the blank.

Speed Trap

You recognise “reason” and answer before checking whether a complete idea or named cause follows.

Memoriser

You know the rule but do not apply it reliably inside a sentence.

Over Thinker

You spend too long debating style when the basic reason pattern already decides the item.

Next practice

Use Grammar Drills to repeat the decision, or Plan Finder to place this page in a broader study sequence.

Grammar DrillsTOEIC Plan Finder
Because vs Because Of Because vs Although Despite vs Although TOEIC Part 5 Guide Grammar Drills Plan Finder
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What’s the difference between “because” and “because of”? “Because” is followed by a full sentence. “Because of” is followed by a noun. Example: I stayed home because it was raining. I stayed home because of the rain. When do I use “because”? Use “because” when what follows has a subject and a verb. Example: She was late because the train stopped. Can I say “because of he was late”? No. That’s incorrect. Use “because” before “he was late.” Say: He was late because he missed the bus. What comes after “because of”? A noun or noun phrase comes after “because of.” Example: The delay was because of traffic. Is “due to” the same as “because of”? Almost, but not always. “Due to” must come after a form of “be,” like “is” or “was.” Example: The delay was due to traffic. Can I start a sentence with “because of”? Yes. Example: Because of the storm, the event was cancelled. Is it wrong to say “due to he was late”? Yes. That is incorrect. Use “because” instead. Say: He was late because he missed the train. When do I use “due to”? Use “due to” after a form of “be” (like is, are, was, were) and before a noun. Example: The cancellation was due to rain. Which is more formal: “because of” or “due to”? “Due to” is a little more formal, but both are used often. Use whichever fits the sentence pattern. Can I use “because” in the middle of a sentence? Yes. Example: He stayed home because he felt sick. Can I say “the flight was cancelled because of it was snowing”? No. That is incorrect. Say: The flight was cancelled because it was snowing. Or: The flight was cancelled because of the snow. What is the most natural way to explain a reason? Use “because” if you have a full sentence after. Use “because of” if only a noun comes after. Do “due to” and “because of” mean the same thing? Yes, they have the same meaning, but they follow different sentence patterns. Can I use “due to” at the start of a sentence? Only if the sentence starts with “It was due to…” or something similar. Example: It was due to a mistake. What’s wrong with “because of she was sick”? It has a sentence after “because of,” so it’s incorrect. Say: She stayed home because she was sick. Is “due” the same as “due to”? No. “Due” by itself doesn’t work in this kind of sentence. Say: The problem was due to poor planning. Can I say “He left due to tired”? That sounds unnatural. Better: He left due to tiredness. Or: He left because he was tired. What do I look for after the blank on TOEIC questions? If it’s a noun, use “because of” or “due to.” If it’s a sentence, use “because.” Can I say “She cried because of she failed”? No. That’s wrong. Say: She cried because she failed. Or: She cried because of her failure. Why does TOEIC ask about these phrases so often? Because they sound similar but follow different patterns. It checks if you notice what comes next — a noun or a full sentence.