inform 后面一定要加of吗?不可以接that么?

不一定,可以接.要看句意.
1、inform sb about/of sth
Please inform us of any change of address as soon as possible.
2、inform sb (that)
We regret to inform you that your application has been rejected.
They decided to inform the police.
3、inform on/against [inform on/against sb] phr v
to tell the police or an enemy information about someone that will harm them
He denied that he had ever informed on his neighbours.
及物动词 vt.
1.通知,告知,报告[(+of/about)]
I informed his wife of his safe arrival.
我通知他太太他已平安抵达.
He informed her he was thinking of entering medical school.
他告诉她他想进医学院.
不及物动词 vi.
1.告发,告密[(+against/on)]
He informed against the drugpusher.
他告发了那个毒品贩.