be sure that 的同义句,为什么是be sure to不是be sure of ,请举例说明

因为后面跟的内容不一样。

be sure that后面加一句完整的句子。如：I'm sure that Simon lives here. Simon lives here. 是完整的句子。

be sure to do sth. 如：They are sure to be late. be late 是一个动词而不是句子

be sure of+名词 如：We're sure of his innocence.

be sure that=be certain that