In this lecture, I can only give you a purely_______view of how we can live life to the full and make some suggestions about the future.

A．precious

B．unique

C．different

D．personal

我国人民发现和使用石油的时间为世界最早。始于何时，据稽考，（）就已开始。

A.至迟在三千多年前

B.至迟在四千多年前

C.至迟在二千多年前