不及物动词怎样变被动语态?

被动语态的构成 由于不及物动词不能带宾语,故无被动语态,
不及物动词构成的短语可以是及物性的,也可以是不及物性的；不及物性的短语动词不可用于被动词态,如look up / down,speak for等。例如：
The fact speaks for itself。（正）
Itself is spoken for by the fact。（误）
但是,不及物动词构成的及物性短语动词可以用于被动语态。例如 ：
That seat has been spoken for。
The man has always been looked upon with disapproval by his wife。
The problem has been gone into。
The bed has been slept in。
Note:
下列短语动词不可构成被动语态：
1。动词+介词→aim for,agree with,admit of,adjust to,come to,become of,belong to;
2。动词+副词→get back,face out,answer back,have on；
3。动词+名词+介词→set sail for,give way to,have a hand in,give place to;
4。动词+副词+介词→keep up with,give up to。例如：
He answered his father back。（正）
His father was answered back。（误）
The committee consists of ten members。（正）
Ten members are consisted of the committee。（误）