Er arbeitete im Garten, derweil seine Frau kochte.

He worked in the garden, meanwhile his wife cooked.

Ich koche das Essen, du kannst derweil den Tisch decken.

I'll cook the meal; you can set the table meanwhile.

Der Chef telefonierte, derweil die Sekretärin die Unterlagen suchte.

The boss was on the phone while the secretary searched for the documents.