TOEIC Link Reading — Part 5 Preposition-versus-Conjunction Strategy: Choosing "because of" vs "because" by What Follows the Blank
One of the most reliable Part 5 traps pairs a preposition with a conjunction that mean nearly the same thing: because of / because, during / while, despite / although, in spite of / even though. The meanings are so close that if you read for meaning alone, both choices sound acceptable and you freeze. The item is not testing meaning at all — it is testing whether you know that a preposition and a conjunction connect to different kinds of grammar. Decide by structure, not by sense, and these become some of the fastest points in the reading section.
The whole decision comes down to one question: does a noun phrase follow the blank, or does a full clause with its own subject and verb? A preposition takes a noun; a conjunction takes a clause. Answer that, and the "which word means the same thing" agony disappears.
Why meaning-first reading fails here
Consider: "The event was postponed __ the storm." and "The event was postponed __ a storm was approaching." In both, the idea is identical — the storm caused the postponement. If you choose by meaning, because of and because are equally tempting in both blanks, and you have a coin-flip.
But grammar decides cleanly. In the first, the storm is a noun phrase, so you need the preposition because of. In the second, a storm was approaching is a clause with its own subject (a storm) and verb (was approaching), so you need the conjunction because. The trap only works on test-takers who read for meaning; it collapses instantly for anyone who checks the structure after the blank.
This is the same "identify the grammatical job before you translate" discipline that drives word-form items, covered in TOEIC Link reading text completion word-form strategy. Part 5 rewards a top-down structural read far more than a meaning-first one.
The one-step test: noun or clause?
After you spot a preposition/conjunction pair in the choices, look at the very next few words after the blank:
- A noun or noun phrase follows (a determiner + noun, a gerund, a pronoun) → choose the preposition.
- A subject + verb follows (a full clause) → choose the conjunction.
That is the entire method. You do not need to understand the sentence's full meaning; you need to classify what comes after the blank.
Watch the gerund exception
The one place this trips people up: a gerund (-ing used as a noun) looks like a verb but functions as a noun. "__ reviewing the contract, she signed it" needs a preposition-style connector because reviewing the contract is a gerund phrase, not a clause with a subject. Compare "__ she reviewed the contract, she signed it," which has the subject she and needs a conjunction. If the "-ing" word has no subject in front of it, treat it as a noun and choose the preposition.
The high-frequency pairs to memorize as pairs
Learn these in preposition/conjunction couples so that when you see one, you automatically look for what follows the blank:
| Meaning | Preposition (+ noun) | Conjunction (+ clause) |
|---|---|---|
| cause | because of, due to, owing to | because, since, as |
| contrast | despite, in spite of | although, though, even though |
| time (simultaneous) | during | while, as |
| time (before/after) | prior to, following | before, after |
| condition | in case of | in case, if |
Note that before, after, and since can work as both preposition and conjunction, so for those the "noun or clause?" test tells you which grammar is in play rather than which word to pick — but the pairs that share a row above are strictly one-or-the-other, and those are the trap items.
The reverse trap: same word, two structures
The test also runs the trap backwards. It gives you one connector and two continuations, or embeds the connector so you must supply the right following structure. When a sentence already contains because, expect a full clause after it; if the sentence offers you a noun-phrase continuation, because is wrong and the answer is a different structure entirely. Reading the connector and its required complement as a matched pair — the same "frame first, details second" habit that speeds purpose questions in TOEIC Link Part 7 inference and not-stated questions in single passages — keeps you from being surprised by what has to follow.
A quick worked example
"__ the heavy rain, the outdoor ceremony proceeded as planned."
Choices: (A) Although (B) Despite (C) Even though (D) While
Look after the blank: the heavy rain — a determiner (the) plus adjective plus noun. That is a noun phrase, not a clause. So you need a preposition of contrast: Despite. Choices A, C, and D are all conjunctions and would require a full clause (although it rained heavily). You did not have to weigh whether the ceremony proceeding "contrasts" with the rain — the noun phrase after the blank settled it in one second.
How to build the habit
- See the pair, look right. The instant you notice a preposition/conjunction pair in the choices, move your eyes to the words after the blank, not to the meaning of the sentence.
- Classify: noun or subject+verb? Say it silently. Noun → preposition. Subject+verb → conjunction. Nothing else.
- Flag gerunds. An "-ing" word with no subject in front is a noun; do not mistake it for a clause.
- Drill the pairs, not the singles. Memorize because of / because as a unit so the structural test fires automatically.
Preposition-versus-conjunction items are pure structure dressed up as meaning. Stop asking "which one makes sense" — both do — and start asking "noun or clause?" That single question converts a common freeze into a two-second point every time it appears.