We are of course _______ that the period for completion of your

We are of course _______ that the period for completion of your project has already been exceeded.
A、know
B、to know
C、aware
D、sure
【正确答案】：C
【题目解析】：be aware that意识到
句意：我们当然知道你们的项目已经超过了完成期限。