That is, I think, the sort of historical basis and to the present, the highest objective of the work.

我认为，这是一种历史根基，也是目前工作的最高目标。

Well, there's a historical basis  for the fact that passengers almost always board aircraft from the left-hand side.

好吧，乘客几乎总是从左侧登机这一事实是有历史依据的。

The historians all said that the book is completely false, there isn't any historical basis in the main idea in the book.

历史学家们都说这本书完全是假的，书中的主要思想没有任何历史依据。