首先说明：as long as 跟as long ago as 不是一回事。

as long ago as... 放在句中，总体看它是时间状语；内部细分的话，又是个比较结构。放在句中一般理解为时间状语即可。

一、as long as 有两层意思：1. 跟......一样长；2. 只要（用作从属连词，引导条件从句）

This line is four times as long as that one. 这条线是那条线的四倍长。

You can keep my book as long as you like. 我的书你要借多久都随你的便。

二、as long ago as，表示时间概念，之后接时间名词。意为“早在......之前”， as long ago as 1911：“早在1911年之前”。

Silk was made in China as long ago as 3200 BC. 早在公元前3200年中国就制作出了丝绸。

As long ago as the eleventh century the Chinese people not only invented the compass but also used in navigation. 早在十一世纪中国人就不仅发明了指南针,而且把它用于航海。