English Help Online's Blog

A few people have asked me about the difference between “because” and “since”, so that’s what I’ll write about today.

Generally speaking, we use “because” to state the reason for something that the listener or reader doesn’t already know, or when it’s uncertain if they know or not. We use “since” to emphasize the reason for something that is already known to the listener or reader. For example:

I went to Hawaii because I wanted to visit my friend there.

Because my best friend lives in Hawaii, I often go there to visit her.

Since my best friend lives in Hawaii, I often go there to visit her.

You shouldn’t let your children play around here because it’s a dangerous area.

Because this is a dangerous area, you shouldn’t let your children play around here.

Since this is a dangerous area, you shouldn’t let your children play around here.

I’m really nervous because this is my first time to give a presentation at work.

Because this is my first time to give a presentation at work, I’m really nervous.

Since this is my first time to give a presentation at work, I’m really nervous.

So, in the examples above I first used “because” in the middle of the sentence. This indicates that the speaker thinks they are stating a reason that the listener doesn’t know.

After that, I used “because” at the beginning of the sentence. This indicates that the speaker isn’t sure if the listener knows the reason or not.

Finally, I used “since” at the beginning of the sentence. This indicates that the speaker thinks they are stating a reason that the listener already knows.

My statement about using “because” at the beginning of a sentence is not a strict rule but, in my opinion, it’s a good guideline for when to use “because” at the beginning of a sentence.

In English, we often do something called speculating. This means that, when we don’t know the reason for something, we make suggestions about what the reason could be. We also often speculate about another person’s feelings about a certain situation. We use the words “must” and “might” to do this, but many people are confused about which one to use in each situation. That’s what I’d like to go over in my blog today.

We use “must” when we think there is only one possibility. For example:

A: Why is Jack late for the party?

B: He’s working on a big project now, so he must still be at the office.

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A: Why was Beth talking so strangely last night?

B: She must have been drunk. She’s always talks like that when she drinks too much.

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A: My sister and her husband are going to have their first baby!

B: That’s wonderful news! They must be so happy and excited!

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A: When I was young, I wanted to get into Harvard, but I couldn’t.

B: You must have been so disappointed.

We use “might” when we think there is more than one possibility. For example:

A: I don’t know why Ken cancelled our plans for tonight.

B: He might be sick. A lot of people are getting a cold nowadays.

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A: Our neighbor’s house burned down last year. I wonder how the fire got started.

B: It might have been started by a gas leak, or it might have just been some kids playing with matches.

We can also use the words “may” and “could” instead of “might”. The words “might” and “could” are both used in normal conversations but the word “may” is a little more formal.

Please note in the examples the use of the past tense: we use “must have” and “might have” to indicate a past situation.

Also, please note that we can use “must” or “must have” to talk about either reasons or feelings, but we DON’T use “might” or “might have” to talk about feelings.