请问It's said that by us从句是被动语态,怎么It's known to us that从句却不是?请问It's said that by us从句是被动语态,这里用的是BY US,而It's known to us that...这句用TO US ,也可以是被动语态?好象不是被动语

请问It's said that by us从句是被动语态,怎么It's known to us that从句却不是?
请问It's said that by us从句是被动语态,这里用的是BY US,而It's known to us that...这句用TO US ,也可以是被动语态?好象不是被动语态了?

by us被我们……（by 就是被动语态的标志之一）
to us 对我们来说……（It is +形容词+to/for +sb 是一种习惯用法、固定的句式,不是被动语态）