I know the answer is C.But I can't understand the reason why the sentence is used "before".What's different from "It will take three months for us to deliver to you."?
そうです!英語では従属節が使われると、接続語は主節に繋ぐために使われます。英語では「That」や「In which」などの単語を使います。でも、そういう言葉は省略ができます! 例えば、 My parents found an old game that I played as a child. My parents found an old gam