From an Opinion to a Justified Opinion
The phrase I think this plan is useful states a position but does not explain it. A justification answers an explicit or implied question Why?: I think this plan is useful because it saves time.
The reason must support the exact opinion expressed. A grammatically correct clause is not a good justification if it does not explain the position or conflicts with the facts of the situation.
At B1 level, it is enough to state an opinion clearly and add one or two relevant reasons. This rule does not require a complex essay or proof of scientific causation.
opinion + because / since / as + subject + verb
- subject / S —
- The grammatical subject: who or what the clause is about; the verb agrees with it. In The book was written, the book is the subject, although someone else does the action.
- verb / V —
- A word for an action or state, such as work or be. The pattern determines its form.
I think the evening class is useful because more people can attend.
I think the evening class is useful because more people can attend.
The clause after because directly explains the opinion expressed.
In my view, the park needs more benches because older visitors need places to rest.
In my view, the park needs more benches because older visitors need places to rest.
The reason is specific and logically supports the proposal.
Because Introduces a Complete Reason Clause
Because is a conjunction. It is usually followed by a clause with its own subject and verb: because the room is quiet, because we can walk there, because it will reduce waste.
Because is most often used when the reason is important new information or a direct answer to Why?. It is the clearest universal choice for everyday conversation and writing.
Do not double conjunctions: for because and because so do not form one correct causal construction.
because + subject + finite verb
- subject / S —
- The grammatical subject: who or what the clause is about; the verb agrees with it. In The book was written, the book is the subject, although someone else does the action.
- verb / V —
- A word for an action or state, such as work or be. The pattern determines its form.
We should repair the bikes because many students use them.
We should repair the bikes because many students use them.
After because, there is a subject, many students, and a verb, use.
Why did you choose the night train? — Because it was cheaper.
Why did you choose the night train? — Because it was cheaper.
In a conversational answer to Why?, a clause beginning with Because can stand as a separate reply.
Because, Since, and As: One Reason, Different Focus
Because, since, and as can introduce a reason, but they do not always sound the same. Because more often focuses on a new reason. Since and as often present the reason as an already known or background fact, making the result or decision more important.
Since and as are slightly more formal than because and can have other meanings: since can also refer to time, and as can mean when or in the role of. If the context allows confusion, because is clearer.
In a question where the speaker is checking a suggested reason, because is natural: Are you leaving because the last bus is at ten?
Because the price matters most, I prefer the basic plan.
Because the price matters most, I prefer the basic plan.
Because makes the reason the clear focus.
Since everyone already has the document, I think we can vote now.
Since everyone already has the document, I think we can vote now.
Since presents a commonly known fact as the background for a decision.
As the agenda is short, I suggest a thirty-minute meeting.
As the agenda is short, I suggest a thirty-minute meeting.
As naturally introduces a background reason before the main suggestion.
Clause Order and Punctuation
The reason often comes after the opinion: I support the change because it gives us more time. In this neutral order, a comma is usually not placed before because.
The reason clause can be moved to the beginning to provide background before the decision: Because the road gets busy later, we should leave at six. We place a comma after the initial subordinate clause.
The change in order should not change who does what, the opinion itself, or the reason.
I prefer the smaller room because it is easier to hear everyone.
I prefer the smaller room because it is easier to hear everyone.
First comes the position, then the reason; no comma is needed before because.
Because it is easier to hear everyone, I prefer the smaller room.
Because it is easier to hear everyone, I prefer the smaller room.
The initial reason clause ends with a comma.
The Frames the reason is that and this is because
The main reason is that ... names the reason explicitly and helps structure the explanation. A complete clause follows is that: The main reason is that the route is safer.
The expanded frame The reason (why) I prefer X is that Y connects a specific opinion with a reason. It is a reliable model in neutral edited text.
This is because ... explains a previous statement in a separate sentence. This must clearly refer to the previous idea; otherwise, the reader will not know what exactly is being explained.
The form the reason is because occurs in real usage, so it should not automatically be called ungrammatical. In this lesson, we practise the reason is that as a structured neutral frame.
The reason (why) + opinion + is that + clause | statement. This is because + clause.
- clause —
- A construction with a verb, often with its own subject: when I arrived. A non-finite clause may leave the subject unspoken: to get home.
The main reason I support the plan is that it protects the local library.
The main reason I support the plan is that it protects the local library.
That introduces a complete reason clause after the frame the main reason.
Online meetings can be tiring. This is because people have fewer natural breaks.
Online meetings can be tiring. This is because people have fewer natural breaks.
This is because explains the entire previous statement.
Because and Because Of—Different Follow-ups
Because introduces a clause with a subject and a verb: because the traffic is light. Because of is a prepositional construction before a noun phrase: because of the light traffic.
The meaning may be similar, but the forms cannot be mixed: because of the train was late is incorrect because a complete clause follows because of.
This contrast is needed as a boundary for the rule. The main goal of the lesson is to justify opinions, not to learn every prepositional way of expressing a reason.
I prefer this route because the traffic is lighter.
I prefer this route because the traffic is lighter.
After because, there is the clause the traffic is lighter.
I prefer this route because of the lighter traffic.
I prefer this route because of the lighter traffic.
After because of, there is the noun phrase the lighter traffic.
Using It in Conversation and Short Texts
In a dialogue, first listen to exactly what the other person is asking. You can answer Why? with Because + clause. In a formal standalone sentence, add the main clause so that the text does not remain a fragment.
For a short justification, state the position, add a relevant reason, and, if needed, add one more independent reason. Do not repeat the same idea in different words instead of explaining it.
Your own examples may be true or invented. Self-checking evaluates the content, the target construction, grammar, and appropriateness—not whether it matches the model.
I recommend the Saturday class because most people are free then. Another reason is that the room is quieter at weekends.
I recommend the Saturday class because most people are free then. Another reason is that the room is quieter at weekends.
Two different reasons support one recommendation without mechanical repetition.
I do not support the change. I say this because it would make the service less accessible.
I do not support the change. I say this because it would make the service less accessible.
I say this because clearly refers back to the previous position.
Common mistakes
Incorrect:I think the library should open later for because many people work until six.
Correct:I think the library should open later because many people work until six.
For and because do not combine into one double conjunction; for an ordinary reason clause, because is enough.
Incorrect:I support the change because of it gives staff more time.
Correct:I support the change because it gives staff more time.
After because of, a noun phrase is required, but it gives staff more time is a complete clause, so because is needed here.
Incorrect:The main reason is that saves both time and money.
Correct:The main reason is that it saves both time and money.
A complete clause is required after that; the subject it is missing before saves.
Incorrect:We should repair the bikes because are useful for students.
Correct:We should repair the bikes because they are useful for students.
A reason clause needs the explicit subject they before are.
Incorrect:I prefer the basic plan because it will saves money.
Correct:I prefer the basic plan because it will save money.
After the modal will, use the base form save, not saves.