関係副詞howは、先行詞が方法を表す名詞(主にthe way)で、かつ、関係代名詞が副詞句の一部になっているとき用いられる。原則として、the wayかhowのどちらか一方を省略して用いる。
- That's the way (how) Mary and I became friends again.
- That's (the way) how Mary and I became friends again.
- = That's the way in which Mary and I became friends again.