なので

In a sentence

• 私は学生なので、毎日勉強しなければなりません。

  Since I am a student, I need to study every day.

  Here, 'なので' is used to connect a reason ('I am a student') to a consequent action ('I need to study').

• 今日は休日なので、友達と遊びに行きます。

  Because today is a holiday, I will go out with my friends.

  In this sentence, 'なので' links the cause ('today is a holiday') with a suitable outcome ('I will go out with my friends').

• 彼は外出しているので、家に誰もいません。

  As he is out, nobody is at home.

  Here, 'なので' connects a reason ('he is out') to its resultant state ('nobody is at home').