What's the difference between にかけてand にわたって?


It looks like にわたって has just one meaning, "over (a period of time)" whereas
にかけて means "over (a period of time)" and also "until". Is that correct? Can
they be used almost interchangeably?




They are different. You use かけて with an endpoint, and わたって with a span.

> 20世紀の終わりにかけて ...  
>  今夜にかけて ...
>
> 3世紀に渡って ...  
>  3世代に渡って ...




They are different. You use かけて with an endpoint, and わたって with a span.

> 20世紀の終わりにかけて ...  
>  今夜にかけて ...
>
> 3世紀に渡って ...  
>  3世代に渡って ...

