2つの節を however(しかしながら)や moreove(さらに)などの接続副詞でつなぐ場合に、セミコロンを用いることがあります。本来はピリオドを付けて別々の文にするものなので、カンマで代用することはできません。
○ You said that the design would be finished on January 3; however, it is already March 1.
○ You said that the design would be finished on January 3. However, it is already March 1.
× You said that the design would be finished on January 3, however, it is already March 1.
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