To express a reason or cause in Japanese, から（kara）, ので（node）, and で（de）are quite useful.
Although they all mean "because" or "since," they are used a bit differently.
For starters, "kara" is a bit more casual, "node" a bit more formal.
"Kara" is used in more emotional, personal situations.
忙しかったから行かなかった。（Isogashikatta kara ikanakatta.) I was busy so I didn't go.
This is perhaps not the most persuasive or logical sentence--but it and others like it are often heard.
"Node" implies you are being logical. Using the same sentence:
忙しかったので行きませんでした。（Isogashikatta node ikimasen deshita.) I was busy (with something logical and important!) so I didn't go.
The final possiblility, "de" （で）, is often used in the sense of "because of...," and is used in front of a noun.
For example, 雨で遅くなりました。(Ame de osoku narimashita.) Because of the rain, I was late.
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Thursday, October 02, 2008