Clauses of Result

Although: Unexpected result

Used for introducing a statement that makes the main statement in a sentence seem surprising SYN though: Although the sun was shining it wasn't very warm. Although small, the kitchen is well designed.
Used to mean "but" or "however" when you are commenting on a statement: I felt he was wrong, although I didn't say so at the time.

Although / even though / though
You can use these words to show contrast between two clauses or two sentences. "Though" is used more in spoken than in written English. You can use although, even though and though at the beginning of a sentence or clause that has a verb. Notice where the commas go: Although/Even though/Though everyone played well, we lost the game. We lost the game, although / even though / though everyone played well.
You cannot use even on its own at the beginning of: a sentence or clause instead of although, even though or though:

• Despite the fact that. SYN although: Anne was fond of Tim, though he often annoyed her. Though she gave no sign, I was sure she had seen me. His clothes, though old and worn, looked clean and of good quality. Strange though it may sound, I was pleased it was over.
• Used to add a fact or an opinion that makes the previous statement less strong or less important: They're very different, though they did seem to get on well when they met. He'll probably say no, though it's worth asking.

Used especially at the end of a sentence to add a fact or an opinion that makes the previous statement less strong or less important: Our team lost. It was a good game though. "Have you ever been to Australia? No. I'd like to, though."

Because

For the reason that: I did it because he told me to. Just because I don't complain, people think I'm satisfied.
Because of: preposition: They are here because of us. He walked slowly because of his bad leg. Because of his wife ('s) being there, I said nothing about it.

Since

(Used with the present perfect or past perfect tense) from a time in the past until a later past time, or until now: She's been off work since Tuesday. We've lived here since 1994. I haven't eaten since breakfast. He's been working in a bank since leaving school. Since the party she had only spoken to him once. "They've split up. Since when?" That was years ago. I've changed jobs since then.
Use for, not since, with a period of time: I've been learning English for five years.
Since when? Used when you are showing that you are angry about sth: Since when did he ever listen to me?

• (used with the present perfect, past perfect or simple present tense in the main clause) from an event in the past until a later past event, or until now: Cathy hasn't phoned since she went to Berlin. It was the first time I'd had visitors since I'd moved to London. It's twenty years since I've seen her. How long is it since we last went to the theatre? She had been worrying ever since the letter arrived.
• Because, as: We thought that, since we were in the area, we'd stop by and see them.

(Used with the present, perfect or past perfect tense)

• From a time in the past until a later past time, or until now: He left home two weeks ago and we haven't heard from him since. The original building has long since (= long before now) been demolished.
• At a time after a particular time in the past: We were divorced two years ago and she has since remarried.