If a place or thing is unreachable, it is not possible to get to it, or to get hold of it.

The village had been unreachable because landslides had blocked the roads. 由于山体滑坡阻断了道路，村子一直进不去。

Sometimes the solution is as simple as lowering the height of a table if crayons and pencils are unreachable. 有时候，解决的办法很简单，如果蜡笔和铅笔拿不到的话，就把桌子高度降低一些。

If a person is unreachable, it is not possible to contact them.

Some tech company offices in major cities were unreachable by phone last Tuesday. 上周二，一些大城市的科技公司办公室无法通过电话联系到。

If a level, especially a high one, is unreachable, it is not possible to achieve.

After achieving a goal thought unreachable so early in the track season, Webb still has much to aim for. 在田径赛季如此之早地实现了人们认为无法企及的目标后，韦伯仍有很多有待实现的梦想。