because / since / as は理由を表す
要点使い分け
because / since / as の使い分け
理由をはっきり述べるなら because、背景として軽く添えるなら since / as。
理由をはっきり述べる — I stayed home because I had a cold.
since / as理由を背景として軽く添える — Since we have time, let's have coffee.
because と because of の違い
後ろに文が続くか、名詞が続くかで使い分けます。
接続詞・後ろは文 — because it rained
because of前置詞・後ろは名詞 — because of the rain
文法の形
接続詞の後ろは文、前置詞の後ろは名詞になります。
because I was tired
because of the rain
文法のルール
because の後ろにはメインの文を足して完全な文にする。
Because I was tired.
I went to bed early because I was tired.
会話の短い返答では Because ... だけで答えることもありますが、文法練習や書き言葉ではメインの文を足して完全な文にします。
because は文が続き、because of は名詞が続く。
I went to bed early because of I was tired.
I went to bed early because I was tired.
because は接続詞なので後ろに主語+動詞の文が続きます。because of は前置詞なので後ろは名詞です。
because と so を同じ文で重ねない。
Because I was tired so I went to bed.
Because I was tired, I went to bed. / I was tired, so I went to bed.
because は理由、so は結果を表します。1つの文で同じ理由と結果をつなぐときは、because と so を重ねず、どちらか一方を使います。