throughout; over a period of ...; over a span of ...
三日間に渡って会議が開かれた。
The meeting was held over a period of three days.
長年に渡って続けてきた研究がまとまった。
Research that had been continued over many years was compiled.
広い範囲に渡って被害が確認された。
Damage was confirmed over a wide area.