后面跟to do的动词变被动语态是什么情况

关于不带to的不定式,举个例子
They did not observe she come in and go upstairs．
被动：
She wasn't observed (by them) to come in and go upstairs.
带doing的就直接变换,因为doing的语法功能大体上相当于一个名词,及物动词直接加doing,不及物动词加介词再加名词/doing
比如：
She was considered having lunch already.
She was devoted to studying computer.(这种情况很别扭,因为一般to doing的都是devote contribute,look forward,prefer之类的很主观的动词)
还有一个超经典的：be used to doing
She was used to sleeping at 9 o'clock.她已经习惯于9点睡觉.
这里边可不是被动语态,used大体相当个形容词