Adverb Clauses of Reason: Because, Since, and As: correct answers

Read the desperate sticky note left on the fridge and choose the right word to start the sentence.

___ we are completely out of coffee, I am borrowing your emergency stash of energy drinks.

The correct answer is Since.

Since is a subordinating conjunction used to introduce an adverb clause of reason, especially when the reason is already known to the listener. When an adverb clause starts a sentence, we place a comma before the main clause. "Because of" requires a noun phrase, while "Therefore" and "So" are used to introduce results, not reasons.

The correct answers are: I am crying because my cat slept on my silk dress. Since my cat completely ruined the fabric, I have nothing to wear.

Adverb clauses of reason must start with a subordinating conjunction (like because, since, or as) and be followed by a complete clause (a subject and a verb).

"Because of" and "due to" are prepositions. They must be followed by a noun phrase (e.g., because of my cat), not a full clause with a verb like "ruined".

Help the panicked office worker choose the grammatically correct excuse to send to the boss.

Select the grammatically correct sentence.

The correct answer is I missed the morning meeting because my cat unplugged my alarm clock.

When an adverb clause of reason comes after the main clause, we typically do not use a comma.

• "Because of" is incorrect because it is followed by a full clause, not a noun phrase.

• If the "because" clause comes first, it requires a comma ("Because my cat unplugged my alarm clock**,** I missed...").

• You cannot use both "since" (reason) and "so" (result) to connect the same two clauses.

The correct answers are: Since the dragon refused to brush its teeth, the villagers relocated to the next valley. As the knights were terrified of fire, they brought giant marshmallows to negotiate.

The conjunctions "since" and "as" can be tricky because they have double meanings! They can act as conjunctions of time OR reason.

In the correct sentences, "since" means because and "as" means because. In the incorrect options, "since" refers to a starting point in time (from 1402 until now), and "as" means while or at the exact moment that.

Complete the starship captain's slightly embarrassing log entry by selecting the correct conjunction.

We had to land on the swamp planet ___ our ship's hyperdrive was making a sound like a dying washing machine.

The correct answer is as.

As can be used as a subordinating conjunction meaning "because" to introduce an adverb clause of reason. "So" introduces a result, "because of" requires a noun phrase instead of a full clause, and "nevertheless" shows contrast.

Help the detective complete her final report by choosing the grammatically correct word.

The suspect couldn't have stolen the diamond ___ he was locked in the police station at the time.

The correct answer is because.

We use the subordinating conjunction because to introduce an adverb clause of reason, which must contain a subject and a verb ("he was locked"). "Because of" and "due to" are prepositions that must be followed by a noun phrase, not a full clause. "Therefore" is an adverb that would require different punctuation (like a semicolon) to connect two independent clauses.

The correct answers are:

I missed the launch because my spacesuit was at the dry cleaners.

When the reason clause comes after the main clause, no comma is needed before "because."

Since my spacesuit was at the dry cleaners, I missed the launch.

When the adverb clause of reason comes before the main clause, a comma is required after it.

The incorrect options:

"Because my spacesuit was at the dry cleaners I missed the launch." is wrong because a fronted adverb clause must be followed by a comma.

"I missed the launch, since, my spacesuit was at the dry cleaners." is wrong because "since" should not be surrounded by commas; it is a conjunction introducing a clause, not a parenthetical.