Question said:Is it true that you only use since if the reason is obvious and because if not?
For example, my readers know that my friend is blind but they don't know that he can play the piano:
a) I need to guide my friend since he is blind.
b) My friend wants me to buy him a keyboard because he knows how to play the piano.
I used to think that they are synonyms so I kept on interchanging them.
Can we say "conclusion" in place of "conclusions"?Answer said:I would have said that because and since were interchangeable in either sentence, but more people (at least probably AmE speakers) choose because and use since more often to refer to time instead of a reason for something. No source or corpus used here, just natural conclusions.