You can use untold to emphasize how bad or unpleasant something is.
Landmines have caused untold misery to thousands of innocent people.
地雷已给成千上万无辜的人带来了不可名状的苦难。
You can use untold to emphasize that an amount or quantity is very large, especially when you are not sure how large it is.
the nation's untold millions of anglers.
该国数百万的钓鱼爱好者。