English guide
Distinguish reason clauses from cause phrases and practise because, because of and due to with workplace examples and full option explanations.
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What this guide covers
Compare the explanations and original examples.
Keep the sentence unchanged and justify one option.
Use the distinction in a new workplace sentence.
The useful distinction is usually what follows the expression. Because the lift is being repaired contains a subject and a finite verb. Because of the lift repairs packages the same cause as a noun phrase. Read past the gap before deciding which structure fits.
Because of and due to can both introduce a cause phrase in modern usage, so a fair question should not pretend that only one can precede the same noun phrase. The items below use fixed surrounding words or contrasting clause structures to make the intended answer clear. They also separate a real cause from a surprising contrast.
These original exercises were prepared by English AIdol with AI assistance. A separate AI content review checked every question, answer explanation and teaching section. No human expert or examiner review, ETS endorsement, or calibrated difficulty is claimed. This page does not save answers or estimate an official score.
Part 5 asks you to complete sentences by choosing from four options. The full TOEIC Reading section has 100 questions and a 75-minute limit. This untimed topic lesson is not a complete or equated test. See ETS: About the TOEIC Listening and Reading Test and the ETS: TOEIC Listening & Reading Score User Guide.
A reason clause has its own subject and verb. Because introduces that clause; do not insert of before the subject.
A noun phrase names the cause without making a separate subject–verb statement. Because of and due to can both introduce it; avoid making their overlap a false test distinction.
The fact that ... can follow because of or due to. In concise writing, because plus the clause is often simpler; grammatical and stylistic judgments are different.
A reason explains an outcome. Despite introduces an obstacle that did not prevent it, and during gives a time period. Check the stated relationship as well as the words immediately after the gap.
The delivery was postponed ___ the bridge was closed.
because
The bridge is the subject and was closed is the finite verb phrase. Because introduces this reason clause. Because of the bridge closure would be a valid rewrite, but it changes the printed words.
Choose the option that completes the printed sentence in standard written English. Keep every other word unchanged. Write your choice and a reason before opening the explanation.
The presentation began late ___ the projector had stopped working.
(A) because of
(B) because
(C) due to
(D) owing to
Answer: (B) because
Completed sentence: The presentation began late because the projector had stopped working.
The lift is out of service because ___ scheduled maintenance.
(A) to
(B) for
(C) from
(D) of
Answer: (D) of
Completed sentence: The lift is out of service because of scheduled maintenance.
The discrepancy was due ___ a duplicate entry in the sales ledger.
(A) to
(B) of
(C) for
(D) with
Answer: (A) to
Completed sentence: The discrepancy was due to a duplicate entry in the sales ledger.
___ several delegates are joining remotely, the organiser will test the audio first.
(A) Because of
(B) Due to
(C) Because
(D) During
Answer: (C) Because
Completed sentence: Because several delegates are joining remotely, the organiser will test the audio first.
The shipment was held at customs ___ an unsigned declaration.
(A) because
(B) because of
(C) since that
(D) as that
Answer: (B) because of
Completed sentence: The shipment was held at customs because of an unsigned declaration.
The delay was due to the ___ that two labels carried the same tracking number.
(A) factual
(B) factually
(C) factors
(D) fact
Answer: (D) fact
Completed sentence: The delay was due to the fact that two labels carried the same tracking number.
We selected this venue ___ it has step-free access to every meeting room.
(A) because
(B) due to
(C) because of
(D) in spite of
Answer: (A) because
Completed sentence: We selected this venue because it has step-free access to every meeting room.
The cancellation was ___ to a shortage of qualified drivers.
(A) because
(B) owing to
(C) due
(D) caused
Answer: (C) due
Completed sentence: The cancellation was due to a shortage of qualified drivers.
The inspection found a dangerous leak; the restaurant closed ___ this safety risk.
(A) despite
(B) because of
(C) although
(D) because
Answer: (B) because of
Completed sentence: The inspection found a dangerous leak; the restaurant closed because of this safety risk.
The extra charge arose because of the fact ___ the parcel exceeded the size limit.
(A) which
(B) what
(C) whose
(D) that
Answer: (D) that
Completed sentence: The extra charge arose because of the fact that the parcel exceeded the size limit.
The account remains locked because the user ___ the wrong password repeatedly.
(A) entered
(B) entering
(C) to enter
(D) entry
Answer: (A) entered
Completed sentence: The account remains locked because the user entered the wrong password repeatedly.
Because of a ___ of storage space in the archive, older boxes will be moved off-site.
(A) short
(B) shortly
(C) shortage
(D) shorten
Answer: (C) shortage
Completed sentence: Because of a shortage of storage space in the archive, older boxes will be moved off-site.
The invoice was returned ___ the purchase-order number was missing.
(A) owing to
(B) because
(C) because of
(D) on account of
Answer: (B) because
Completed sentence: The invoice was returned because the purchase-order number was missing.
A sudden power failure was the cause of the stoppage; the stoppage was ___ the power failure.
(A) because
(B) although
(C) during of
(D) due to
Answer: (D) due to
Completed sentence: A sudden power failure was the cause of the stoppage; the stoppage was due to the power failure.
The supplier withdrew because ___ fact that the required material was unavailable.
(A) of the
(B) of
(C) the of
(D) to the
Answer: (A) of the
Completed sentence: The supplier withdrew because of the fact that the required material was unavailable.
The street was flooded, making the entrance unusable; deliveries were diverted ___ the flooding.
(A) in spite of
(B) although
(C) because of
(D) because
Answer: (C) because of
Completed sentence: The street was flooded, making the entrance unusable; deliveries were diverted because of the flooding.
Because the loading area ___ icy, staff used the covered entrance instead.
(A) being
(B) was
(C) to be
(D) been
Answer: (B) was
Completed sentence: Because the loading area was icy, staff used the covered entrance instead.
The increase in response time is due to ___ network congestion during peak hours.
(A) severely
(B) severity
(C) is severe
(D) severe
Answer: (D) severe
Completed sentence: The increase in response time is due to severe network congestion during peak hours.
___ the client requested a different finish, the workshop revised its quotation.
(A) Because
(B) Due to
(C) Because of
(D) On account of
Answer: (A) Because
Completed sentence: Because the client requested a different finish, the workshop revised its quotation.
Due to a ___ in demand, the distributor rented an additional warehouse.
(A) rose
(B) risen
(C) rise
(D) risingly
Answer: (C) rise
Completed sentence: Due to a rise in demand, the distributor rented an additional warehouse.
Explain the distinction in your own words, then try these tasks without copying a practice sentence. The answers illustrate possible responses; alternatives may work where the task allows them.
Rewrite “The session ended early because the network failed” using because of.
The session ended early because of a network failure.
Replace the clause the network failed with the noun phrase a network failure.
Shorten “The delay was due to the fact that the driver was ill” using because.
The delay occurred because the driver was ill.
Because introduces the retained reason clause directly. The original is grammatical but more wordy.
Can both “because of snow” and “due to snow” describe a delayed flight?
Yes. Both can introduce the snow as the cause of a delay.
The lesson does not impose an outdated blanket ban on due to modifying an event.
Sources checked on . The examples, questions and explanations are original teaching material, not official or recalled test items. This correction replaces the earlier lesson’s inappropriate IELTS-style scoring. An answer count on these exercises does not convert to an official TOEIC score.
Continue with the TOEIC study page. For a factual correction, see our editorial policy.
No. Modern usage includes event descriptions such as a service delayed due to a fault. After be is a useful pattern, not the only valid one.
Use because for an ordinary finite reason clause. Because of the fact that can introduce that clause through the noun fact, but usually adds unnecessary words.
They can both fit before the same cause phrase. These questions test differences that the printed structure or meaning actually supports.
No. These original, untimed teaching questions have not been equated to an ETS form. Use them to explain and practise a language pattern, not to calculate an official score.