At that time, the general public was/ were not aware of the health risks.

　　那時(shí)，公眾對(duì)各種危及健康的因素尚不了解。

　　She was aware that she was losing all sense of perspective.

　　她意識(shí)到自己正在失掉一切正確判斷的能力。

　　I'm aware of Mark's reputation for being late.

　　我知道馬克遲到是出了名的。

　　Were you at any time aware of a quarrel between the two of them?

　　你什么時(shí)候注意到他倆拌過(guò)嘴嗎？

　　She slipped away without him being aware of it.

　　她悄悄離開，沒(méi)有讓他發(fā)覺(jué)。