unthinkable

an unthinkable amount of money.

数目庞大得无法象一笔钱

it was unthinkable that John could be dead.

约翰会死到。

It would be unthinkable to ask him to do that.

叫他做那件事是毫无可能。

That this project would achieve ultimate success was unthinkable at the time.

这个项目能获得最后成功在当时对人们来说是难以置信

It is quite unthinkable that a child like him can speak a foreign language so fluently.

像他这样孩子居然能流利地说一种外语, 是令人难以置信。