It looks like you are using an old version of Internet Explorer. Sorry, we only support IE 10 and above. To use the site you will need to use a more up to date browser. We strongly recommend you upgrade to:

Depending on the context, 'because', 'since', 'as', and 'for' can have the same meaning. I imagine that these conjunctions are in the order of informality, plausibility, or causality.

マーク・ピーターセン『実践 日本人の英語』(岩波新書)が参考になります。
http://www.amazon.co.jp/実践-日本人の英語-岩波新書-マーク・ピーター...

the difference between “because” and “since”
"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."

http://englishhelponline.me/2011/02/

The difference in use between 'because', 'as', 'since' and 'for'
http://www.bbc.co.uk/worldservice/learningengli...

"Because is used when the reason is the most important part of the sentence or utterance. The because clause usually comes at the end."

"As and since are used when the reason is already well known and is therefore usually less important. The as or since clause is usually placed at the beginning of the sentence."

"For suggests that the reason is given as an afterthought. It is never placed at the beginning of the sentence and is more characteristic of written, rather than spoken English."

Because of your post I now feel the urge to comment. As I post too often in any case this contribution is no doubt not necessary. Since I am at it, though, I'll add another sentence. For me to let a day go by without at least one forum post is quite hard, for it has become part of my daily routine on LingQ.

I try my best never to use 'as' in this way when I write. It just leads to difficult and ambiguous sentences.

- As I was on the train, I didn't want to talk on the phone.

This has two meanings

1. While I was on the train, I didn't want to talk on the phone.
2. Because I was on the train, I didn't want to talk on the phone.

Since can also be ambiguous.

- Since I was on the train, I didn't want to talk on the phone.

This can mean

1. I have not wanted to talk on the phone since that time I was on the train.
2. Because I was on the train, I didn't want to talk on the phone.

However, I don't find 'since' to be as confusing as 'as'. I think it is just best to use 'because' and not try to sound elegant.

@ Sanne T - You and I sound 'elegant' in our everyday speech :)~

@ColinJohnstone As we don't go in for "Haarspalterei" here on LingQ, I'll elegantly let your ambiguity statements stand.

When I wrote that last post, I was thinking more about technical writing, for some reason. I have come across quite a few statements that are unclear because of the use of 'as' to mean 'because', but this is mostly in technical physics papers. Whenever I find myself writing 'as' in this way, which is often, I change it to 'because', which seems more crude, but is clearer.

I don't think in normal writing it makes a difference which one is used.

To comment login or sign up for a free account