副詞節は動詞、形容詞、他の副詞を修飾します。いつ、なぜ、どのように、どんな条件でかを答えます。
時間： when, while, before, after, until, as soon as, once
理由： because, since, as, now that
条件： if, unless, provided that, as long as
譲歩： although, even though, while, whereas
重要： 節（S+V）の前には接続詞を、名詞の前には前置詞を使います。
| 接続詞（+ 節） | 前置詞（+ 名詞） |
| although | despite / in spite of |
| because | because of / due to |
| while | during |