We know of the incident, but have no further details.我们听说过这件事, 但对详情不是很清楚。

I know of no one who would want to murder Albert.我从未听说过有人想谋杀艾伯特。

The president admitted that he did not know of any rebels having surrendered so far.总统承认, 据他所知迄今为止还没有反叛者投降。