再急也要将完整的句子抄上来.
经搜索,网上找不到你这一题.很有可能是改自下面这题：
Smokers are well ___C___ of the the dangers of smoking to their own health,but they just can't do without it.
A.ashamed B.proud C.aware D.awful
改为：
Though _____ the the dangers of smoking to their own health ,they just can't do without it.
A.be aware of B.aware of
答案是B
这是状语从句的省略,当从句中的主语= 主句主语,且谓语中有be动词,可以省略主语+Be
=Though (they are) aware of .,they just .