各国的科学家意识到威胁人类生存环境的那些严峻事实，向人类发出了严重的警告。

各国的科学家意识到威胁人类生存环境的那些严峻事实，向人类发出了严重的警告。
【正确答案】：Aware of the harsh facts concerning the dangers to the environment,scientists in various countries have sounded a serious warning to mankind.